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Photo Forum / Digital Photography / DSLR Cameras / February 2010Autofocus observation
Gear: Canon 5D2, 24-105; 50/1.2; 100-400 zoom. Works well, compact, etc. I was googling through some other stuff tonight and found myself checking out lens reviews, in this case, specifically the 50/1.2. Biggest complaint was that it just wasn't that much sharper than the 1.4 and cost a lot more. And then there was the complaint that the 1.2 generally had auto-focus problems, such that it had to be tweaked in-camera via microadjustments, etc. So I'm reading all this and thinking I had no clue about what they were talking about. I finally gathered that the lack of sharpness was actually focusing error, at least so a few reviewers seemed to think. So I looked at what I've gotten, read my notes, and concluded that I thought the lens was sharp enough that I could routinely get very clear 100% crops. Couldn't think what their problem was. Now, I have that lens for the immaculate control of DOF it provides (well, and then there's the fact that it's the only Canon 50 that handles like a lens should handle...). So I'm obviously aware that point of focus is a primary artistic concern, etc, etc, etc. And in that case, it's always on a tripod and with manual focus via Live View at 10x. But there are also the grab shots with AV and autofocus in bangshooter mode. And sharpness has never been a problem. I think I figured out what their problem might well be, hence this post. Like all(?) DSLRs, the Canon's have a configurable autofocus point assortment, where (I gather) a common configuration is to have them all functional at once. Now, I'm not the dimmest bulb in the room, but I could never figure out why that configuration might have value; there was no way that I could see of controlling where the point of focus was going to be. So I've always used just the center focus point and made it my business to use it thus. Focus and reframe: Like that's too much trouble and too slow? Gads! What did we do before autofocus, and the split image prisms were all that was available for dependable focus checking? Anyway, I've always just used the center focus point for bangshooter mode. So I set it up in the automatic autofocus point chooser mode, or whatever you call it, and tried a series of focusing exercises (all tripod mounted so I had no camera movement error). It turned out that the 50/1.2 had a real problem getting exact focus. It would be just out of focus but equally in either direction, as many times behind as in front. WTH!? As soon as I switched the autofocus mode back to the center point, the misfocus problem disappeared. I concluded that the "all points active" mode did indeed present the problem of unpredictable point of focus, and that what was happening was that the autofocus system wasn't focusing where the operator presumed it was. No wonder it wasn't sharp! Now, sez I, it can't really be that simple, so what am I missing here? Can't figure out what I'm not understanding about this, so I'm asking the question here. What am I missing about all this? Thanks for reading. Longfellow > Like all(?) DSLRs, the Canon's have a configurable autofocus point > assortment, where (I gather) a common configuration is to have them all > functional at once. Now, I'm not the dimmest bulb in the room, but I > could never figure out why that configuration might have value; there > was no way that I could see of controlling where the point of focus was > going to be. I only use that mode with AI Servo for subjects in motion. Why Canon makes their DSLRs use all focus points in the basic modes is a mystery, but it sure answers a lot of "why are my photos not sharp?" questions. > Now, sez I, it can't really be that simple, so what am I missing here? > Can't figure out what I'm not understanding about this, so I'm asking > the question here. > > What am I missing about all this? Nothing. :- ) The only thing I'd add for completeness is the recommendation to use a single AF point other than the centre point when DOF is tight enough that recomposition might put the subject outside of it. >> Like all(?) DSLRs, the Canon's have a configurable autofocus point >> assortment, where (I gather) a common configuration is to have them all [quoted text clipped - 6 lines] > their DSLRs use all focus points in the basic modes is a mystery, but it > sure answers a lot of "why are my photos not sharp?" questions. I didn't know that Canon's basic modes had a default autofocus point pattern. But, on reflection, that sounds about what one might expect; basic modes are for the-camera-does-it-all shots, which means the camera has to also choose the point of focus... yeah, it's about honking big DSLRs as jewelry, isnt' it. >> Now, sez I, it can't really be that simple, so what am I missing here? >> Can't figure out what I'm not understanding about this, so I'm asking [quoted text clipped - 7 lines] > single AF point other than the centre point when DOF is tight enough that > recomposition might put the subject outside of it. And that's when the spectre of technique raises its head. For the grab-shooters, that becomes a real problem. For tripod shooters, it doesn't. The problem is that we find ourselves doing both at some point. But these are questions that are apparently irrelevant to the jewelry wearers. Apparently, they don't care enough to figure them out, even though their images are obviously unsatisfactory even to them. I guess that this is what the folk at Canon and Nikon already know quite well enough to exploit to their own profit. And then there are all those guys who write camera technique books. One wonders how many of those wind up gracing some book shelf, not for actual reading, but to impress company. But enough of such morbid thoughts. Thanks for the response. Longfellow >>> Like all(?) DSLRs, the Canon's have a configurable autofocus point >>> assortment, where (I gather) a common configuration is to have them all [quoted text clipped - 9 lines] > I didn't know that Canon's basic modes had a default autofocus point > pattern. More than default - fixed, not adjustable, no choice. If I could I'd delete maybe 80% of the functions of my 450D. Basically, give me an electronic version of an ME Super with AF, Live View, and E-TTL, and I'd be happy as a clam. > But, on reflection, that sounds about what one might expect; basic modes > are for the-camera-does-it-all shots, which means the camera has to also > choose the point of focus... yeah, it's about honking big DSLRs as > jewelry, > isnt' it. I dunno, but why buy a sophisticated tool and not learn how to use it? The problem is the camera makes a dumb choice of which focus point to use (whatever is closest). >> Like all(?) DSLRs, the Canon's have a configurable autofocus point >> assortment, where (I gather) a common configuration is to have them all >> functional at once. Now, I'm not the dimmest bulb in the room, but I >> could never figure out why that configuration might have value; there >> was no way that I could see of controlling where the point of focus was >> going to be. > I only use that mode with AI Servo for subjects in motion. Why Canon makes > their DSLRs use all focus points in the basic modes is a mystery, but it > sure answers a lot of "why are my photos not sharp?" questions. >> Now, sez I, it can't really be that simple, so what am I missing here? >> Can't figure out what I'm not understanding about this, so I'm asking >> the question here. >> >> What am I missing about all this? > Nothing. :- ) > The only thing I'd add for completeness is the recommendation to use a > single AF point other than the centre point when DOF is tight enough that > recomposition might put the subject outside of it. Provided you're not shooting at a wide enough aperture to bring in aperture related focus drift effects, or your camera isn't one of those with a speial wider aperture central AF sensor to help with that, and of course providing the plane on which your camera's AF sensors are mounted is precisely enough aligned with the image sensor plane. If DSLR AF sensors were well enough designed, manufactured, and calibrated, for the above not to matter, they wouldn't be selling so much more finely crafted and adjusted AF sytems on their most expensive models. My impression is that the cheaper DSLRs have AF systems whose defects you probably won't be able to find easily with the kit zoom lens that came with the camera. With respect to lens reviews I've some to a similar conclusion: that most reviewers of lenses with very critical focusing due to very shallow DoF ascribe faults to the lens which are actually faults in their understanding and use of the camera's focusing systems. Just as lots of reviewers ascribe what are really differences in in-camera jpeg processing to be due to the image sensor itself.  SignatureChris Malcolm >> The only thing I'd add for completeness is the recommendation to use a >> single AF point other than the centre point when DOF is tight enough that >> recomposition might put the subject outside of it. > > Provided you're not shooting at a wide enough aperture to bring in > aperture related focus drift effects, ... Irrelevant. > ... or your camera isn't one of those with a speial wider aperture central > AF sensor to help with that, ... Impossible. > ... and of course providing the plane on which your camera's AF > sensors are mounted is precisely enough aligned with the image sensor > plane. Also completely irrelevant. As usual, you have completely failed to comprehend. :- ) >>> The only thing I'd add for completeness is the recommendation to use a >>> single AF point other than the centre point when DOF is tight enough that >>> recomposition might put the subject outside of it. >> >> Provided you're not shooting at a wide enough aperture to bring in >> aperture related focus drift effects, ... > Irrelevant. It affects accuracy of focus when DoF is tight, aperture is large, and the lens is of spherical design, as many of the good popular economical "nifty fifty" (50mm) lenses are. >> ... or your camera isn't one of those with a speial wider aperture central >> AF sensor to help with that, ... > Impossible. Except in the top of the range models from Canon, Nikon, Sony, and very probably more :-) >> ... and of course providing the plane on which your camera's AF >> sensors are mounted is precisely enough aligned with the image sensor >> plane. > Also completely irrelevant. It's not unknown for new cameras to be supplied with slightly tilted AF sensor planes which throw off the focus of the edge AF sensors on one side, or both sides in different directions, etc.. When present it's usually a small enough error that it's not noticeable until you start using the edge sensors for accurate focus with lenses which have shallow enough DoF to make the focus errors easily visible. That usually requires much more critical lenses than the kit zoom. Aligning the AF sensor plane is part of the AF calibration procedure and like generic back or front focus is easily corrected by a service recalibration. > As usual, you have completely failed to comprehend. :- ) As usual you don't know enough to realise your ignorance :-) SignatureChris Malcolm >>>> The only thing I'd add for completeness is the recommendation to >>>> use a single AF point other than the centre point when DOF is tight [quoted text clipped - 8 lines] > the lens is of spherical design, as many of the good popular > economical "nifty fifty" (50mm) lenses are. How is a gross misfocus better than a possible slight focus error? >>> ... or your camera isn't one of those with a speial wider aperture >>> central AF sensor to help with that, ... [quoted text clipped - 3 lines] > Except in the top of the range models from Canon, Nikon, Sony, and > very probably more :-) How is it possible for a special wider aperture central AF sensor to help when the subject is moved outside the DOF after focus is locked? >>> ... and of course providing the plane on which your camera's AF >>> sensors are mounted is precisely enough aligned with the image [quoted text clipped - 12 lines] > generic back or front focus is easily corrected by a service > recalibration. How is a possible slight focus error worse than a gross misfocus? >> As usual, you have completely failed to comprehend. :- ) > > As usual you don't know enough to realise your ignorance :-) As usual, your assumption of superiority disables your curiosity and humility. :- ) >>>>> The only thing I'd add for completeness is the recommendation to >>>>> use a single AF point other than the centre point when DOF is tight [quoted text clipped - 8 lines] >> the lens is of spherical design, as many of the good popular >> economical "nifty fifty" (50mm) lenses are. > How is a gross misfocus better than a possible slight focus error? No idea what you're talking about. >>>> ... or your camera isn't one of those with a speial wider aperture >>>> central AF sensor to help with that, ... [quoted text clipped - 3 lines] >> Except in the top of the range models from Canon, Nikon, Sony, and >> very probably more :-) > How is it possible for a special wider aperture central AF sensor to help > when the subject is moved outside the DOF after focus is locked? I can't imagine how any AF sensor can help you when you've switched focusing off, and I can;t imagine what point you're making by pointing out that sensors you aren't using aren't being of any use. >>>> ... and of course providing the plane on which your camera's AF >>>> sensors are mounted is precisely enough aligned with the image [quoted text clipped - 12 lines] >> generic back or front focus is easily corrected by a service >> recalibration. > How is a possible slight focus error worse than a gross misfocus? >>> As usual, you have completely failed to comprehend. :- ) You're quite right. I completely fail to comprehend any of your questions and answers here. In case you're rushing to tell me that the reason I don't comprehend is because I'm ignorant, that's not the problem here. The problem is your ambiguous terse one word or one sentence rejoinders. That's not a good strategy for having productive discussions. It is however a very good strategy for maximising your chances of being able to accuse people of misunderstanding. SignatureChris Malcolm >>>>>> The only thing I'd add for completeness is the recommendation to >>>>>> use a single AF point other than the centre point when DOF is tight [quoted text clipped - 12 lines] > > No idea what you're talking about. Exactly! What do you need to be able to understand "use a single AF point other than the centre point when DOF is tight enough that recomposition might put the subject outside of it"? AFAICT, whatever ideas you are pursuing have nothing to do with that. >>>>> ... or your camera isn't one of those with a speial wider aperture >>>>> central AF sensor to help with that, ... [quoted text clipped - 10 lines] > focusing off, and I can;t imagine what point you're making by pointing > out that sensors you aren't using aren't being of any use. There you go again! I say "the subject is moved outside the DOF after focus is locked", and you think "you've switched focusing off". My hovercraft is full of eels! (http://en.wikipedia.org/wiki/Dirty_Hungarian_Phrasebook) >>>>> ... and of course providing the plane on which your camera's AF >>>>> sensors are mounted is precisely enough aligned with the image [quoted text clipped - 19 lines] > You're quite right. I completely fail to comprehend any of your > questions and answers here. Yes, because you didn't address my original statement. Go back there and get that, and everything else will make sense. > In case you're rushing to tell me that the > reason I don't comprehend is because I'm ignorant, that's not the > problem here. The problem is your ambiguous terse one word or one > sentence rejoinders. That's not a good strategy for having productive > discussions. It is however a very good strategy for maximising your > chances of being able to accuse people of misunderstanding. All you have to do is respond to what's said. I'm not going to fall into your trap of defending against your hijacks. No matter how sophisticated you make it look, it's still trolling. > Gear: Canon 5D2, 24-105; 50/1.2; 100-400 zoom. Works well, compact, > etc. [] > What am I missing about all this? > > Thanks for reading. > > Longfellow Perhaps the fact that the 1.2 lens may not have a flat field - i.e. the plane of focus is not actually a plane, so precise focussing in the centre of the image may leave the edges out of focus, and focussing on something at the edge may leave the centre out of focus. See: http://toothwalker.org/optics/astigmatism.html Cheers, David >> Gear: Canon 5D2, 24-105; 50/1.2; 100-400 zoom. Works well, compact, >> etc. [quoted text clipped - 11 lines] > > http://toothwalker.org/optics/astigmatism.html My reply here is a tangent, not probably useful to the OP... Stranger still is how that page describes sagittal vs tangential focus, so changing the focus a bit will sharpen up either radial lines or lines tangent to radial. Dang this stuff is complicated. Here's an example of a 50mm f/1.2 Nikkor used too close as per the examples in that page: http://www.flickr.com/photos/edgehill/4212576816/sizes/o/ That is focus stacked so not showing field curvature but astigmatism. Note the sagittal and tangential 'flares' going in opposite directions. Here's another example: http://www.flickr.com/photos/edgehill/4146874451 > Like all(?) DSLRs, the Canon's have a configurable autofocus point > assortment, where (I gather) a common configuration is to have them all > functional at once. Now, I'm not the dimmest bulb in the room, but I > could never figure out why that configuration might have value; Focus on the closest object, of course. Since most people using automodes etc. don't place unimportant stuff in front and have f/3.5-f5.6 lenses, it's a valuable setting. > there > was no way that I could see of controlling where the point of focus was > going to be. Place the closest object with care and let it be your main object. > So I've always used just the center focus point and made it my business > to use it thus. Focus and reframe: Fun, but your focussed-on object will be too close to the lens afterwards. Do the geometry. It may not matter with f/8 or long distances, it does matter with razor-thin DOFs of f/1.2. It's also a bad idea with ETTL and a still not good idea with ETTL2. > Like that's too much trouble and > too slow? Gads! What did we do before autofocus, and the split image > prisms were all that was available for dependable focus checking? How did they do it when they had to focus on ground glass? > So I set it up in the automatic autofocus point chooser mode, or > whatever you call it, and tried a series of focusing exercises (all > tripod mounted so I had no camera movement error). It turned out that > the 50/1.2 had a real problem getting exact focus. It would be just out > of focus but equally in either direction, as many times behind as in > front. WTH!? Your test was broken, obviously. Additionally, no AF guarantees to be spot on, only within a certain band. And the central AF of the 5D2 is more exact with lenses faster than f/2.8, but the other's aren't. -Wolfgang >> Like all(?) DSLRs, the Canon's have a configurable autofocus point >> assortment, where (I gather) a common configuration is to have them all [quoted text clipped - 5 lines] > stuff in front and have f/3.5-f5.6 lenses, it's a valuable > setting. Oh, good grief! Snap-shoot like painting by numbers? Yeah, I guess so. >> there >> was no way that I could see of controlling where the point of focus was >> going to be. > > Place the closest object with care and let it be your main > object. Straight out of the printed material included in a paint-by-numbers kit. The background is unimportant, hence telephone poles growing out of the top of heads... >> So I've always used just the center focus point and made it my business >> to use it thus. Focus and reframe: [quoted text clipped - 3 lines] > f/8 or long distances, it does matter with razor-thin DOFs > of f/1.2. True enough. But then, for me, it comes down to tinkering with the controls while contemplating the image on the groundglass or the digital screen. I guess I'm enough low tech that I'm really behind the curve in all this. > It's also a bad idea with ETTL and a still not good idea > with ETTL2. These are for using flash, right? >> Like that's too much trouble and >> too slow? Gads! What did we do before autofocus, and the split image >> prisms were all that was available for dependable focus checking? > > How did they do it when they had to focus on ground glass? Well, the 35mm cameras I used didn't have ground glass. All the view cameras, tech cameras and field cameras (at least those that I have) do have ground glass, and all require the use of a good magnifier for focusing, of course. >> So I set it up in the automatic autofocus point chooser mode, or >> whatever you call it, and tried a series of focusing exercises (all [quoted text clipped - 9 lines] > > -Wolfgang How broken? I really don't know much about the other Canon DSLRs; the 5D2 is solid, full frame, and weather resistant. And it's big enough to feel comfortable in my hands. I can't justify the 1Ds series monsters, which don't have anything of value to me that the 5D2 lacks. And that's all I know about Canon DSLRs. Yeah, I'm something of a gear head, but diddling with "rare" cameras is not nearly as much fun as chasing images. Longfellow >>> functional at once. Now, I'm not the dimmest bulb in the room, but I >>> could never figure out why that configuration might have value; >> Focus on the closest object, of course. >> Since most people using automodes etc. don't place unimportant >> stuff in front and have f/3.5-f5.6 lenses, it's a valuable >> setting. > Oh, good grief! Snap-shoot like painting by numbers? Yeah, I guess so. You fail to grasp that Canon makes cameras to sell them, not to give you something to w.nk over. And that includes features that you don't use and cannot grasp. Denigrating those that use *their* cameras in ways *you* don't approve surely means you aim for second dimmest bulb. >>> there >>> was no way that I could see of controlling where the point of focus was >>> going to be. >> Place the closest object with care and let it be your main >> object. > Straight out of the printed material included in a paint-by-numbers kit. > The background is unimportant, hence telephone poles growing out of the > top of heads... If YOU build those cameras, the telephone poles would be in focus instead of the heads. So there. >>> So I've always used just the center focus point and made it my business >>> to use it thus. Focus and reframe: >> Fun, but your focussed-on object will be too close to the >> lens afterwards. Do the geometry. It may not matter with >> f/8 or long distances, it does matter with razor-thin DOFs >> of f/1.2. > True enough. So why do you do it? > But then, for me, it comes down to tinkering with the > controls while contemplating the image on the groundglass or the digital > screen. Ah --- the very way to shoot something more active than a glacier. Why do you use AF at all, then? > I guess I'm enough low tech that I'm really behind the curve in > all this. Hint: you've got to replace the sensor after each shot and put it in the bath with the chemicals. >> It's also a bad idea with ETTL and a still not good idea >> with ETTL2. > These are for using flash, right? Read The F...ine Manual. Search The F...ine Web. >> Your test was broken, obviously. > How broken? It gives bad results, yet you don't describe what you did in detail. Hence, it is broken. > I really don't know much about the other Canon DSLRs; the 5D2 is solid, > full frame, and weather resistant. And it's big enough to feel > comfortable in my hands. I can't justify the 1Ds series monsters, which > don't have anything of value to me that the 5D2 lacks. And that's all I > know about Canon DSLRs. That's not even enough to find the shutter button or to switch the camera on. -Wolfgang <snip> I think you'd be best advised to stay away from pranksters; you would risk the denegration of your wildly inaccurate precision, and that could prove deadly, especially to your inerrant sense of righteousness! Good luck. Longfellow > I think you'd be best advised to stay away from pranksters; So you admit being a prankster? Guess I was right then. Your idle threats and pkranking incorrect assertions are snipped for brevity. -Wolfgang My 50/f1.4 is not as sharp at full aperture as two of my (~f4) zoom lenses at 50mm especially around the edges, but what it does do is let in a lot more light! > Gear: Canon 5D2, 24-105; 50/1.2; 100-400 zoom. Works well, compact, > etc. [quoted text clipped - 58 lines] > > Longfellow <snip> > As soon as I switched the autofocus mode back to the center point, the > misfocus problem disappeared. I concluded that the "all points active" [quoted text clipped - 7 lines] > > What am I missing about all this? Not a lot I have just been through a similar exercise with my 5Dii and a f1.4 50mm. (For me it was money, I could not justify the difference in price right on top of shelling out for the body) Like you, I decided the only useful AF/Drive configurations were centre point and one-shot for stuff that is not wildly moving about. For fast action like sport and frisky wild-life, I'm leaning toward centre point with the 6 'hidden' extras and AI servo. I'm still experimenting with techniques of combining that with the variations of AF hold that I found buried in the menus. All the rest of selecting a focus point or relying on the camera to choose either mis-focused or took as much time as manual. The per-lens AF microadjustment was well worth doing carefully. I got a spectacular improvement from my 135mm f2 L and a slightly smaller improvement from the 50mm f1.4 Both will now instantly focus as well as can be achieved manually with 10x live view as long as there enough light. It doesn't need much light. My calibration technique was to start with that scale at an angle malarkey and finish off with more realistic scenes, like swinging the camera up to a stone fence receding at an angle, shoot immediately, then pixel peeping the result to see which rock really was focused sharpest. I tried the same on a borrowed 50mm f1.2 but it was so far out, even on manual focus, that its owner sent it back for repair. I have not seen it since for another go. SignatureTo de-mung my e-mail address:- fsnospam$elliott$$ PGP Fingerprint: 1A96 3CF7 637F 896B C810 E199 7E5C A9E4 8E59 E248 ><snip> >> As soon as I switched the autofocus mode back to the center point, the [quoted text clipped - 14 lines] > 50mm. (For me it was money, I could not justify the difference in price > right on top of shelling out for the body) Yeah, I bought the 50/1.4 and the focus felt gritty and the autofocus was noisy. For comparison, I've got copies of Nikon and Pentax 1.4s and 1.2s. The old K series Pentax lenses blow the Canon and Nikon glass away: Just as sharp and the color from the Canon and Nikon lenses pale in comparison. And those Pentax lenses (Takumar formula) are so well designed and constructed, I guess I just got spoiled. So I got the Canon 1.2 (which, incidentally, is a monster lens) because it felt like a lens should feel. About the price: $1600 for a 50mm lens? Outrageous! But I suppose that's what real quality construction costs nowadays. Trivia tidbit: Pentax didn't make the K series lenses very long, because they rather quickly realized they simply couldn't afford to manufacture them for the price. Hence the M series, which were quite good enough, although not to the K series standards. They were redesigned and they were noticeably smaller. > Like you, I decided the only useful AF/Drive configurations were centre > point and one-shot for stuff that is not wildly moving about. For fast [quoted text clipped - 4 lines] > relying on the camera to choose either mis-focused or took as much time > as manual. Okay, it looks like I've got a bit more experimenting (and studying the book) to do. But I guess I question the whole concept of "necessary automation". I remember learning to shoot moving objects, birds, people, and all that. It took some intelligent practice: how to move one's body, how to follow focus, and all that. For exposure in afternoon sunlight, it was one or two stops down from the sunny sixteen and so that was one variable that never entered the picture. I didn't use a drive or winder for a long time, and so thumb technique was important. All issues about which young folk nowadays have no clue. So a reasonable question might be: was that any harder to do than all the bells and whistles of these electronic wonders? If not, the new gear does have completely manual mode... > The per-lens AF microadjustment was well worth doing carefully. I got a > spectacular improvement from my 135mm f2 L and a slightly smaller > improvement from the 50mm f1.4 I did read about that. Your recommendation is that I at least check them out. I will do so, and thanks for the heads up. > Both will now instantly focus as well as can be achieved manually with > 10x live view as long as there enough light. It doesn't need much [quoted text clipped - 7 lines] > manual focus, that its owner sent it back for repair. I have not seen > it since for another go. I recall reading some review that said the same thing. I'm happy to report that I've as yet not found a reason to return that lens. Thanks for sharing your experiences! Longfellow > Yeah, I bought the 50/1.4 and the focus felt gritty and the autofocus > was noisy. For comparison, I've got copies of Nikon and Pentax 1.4s and [quoted text clipped - 7 lines] > lens? Outrageous! But I suppose that's what real quality construction > costs nowadays. The Nikon 50/1.2 I got used was $500 and it's not a groundbreaking optic, not particularly big, just useful in low light. They still sell them new, the old manual design. The 35mm f/1.4 is similar but more useful IMO. >> Yeah, I bought the 50/1.4 and the focus felt gritty and the autofocus >> was noisy. For comparison, I've got copies of Nikon and Pentax 1.4s and [quoted text clipped - 12 lines] > them new, the old manual design. The 35mm f/1.4 is similar but more > useful IMO. Hmmm... That looks close to the prices I've seen on Ebay, interestingly enough. I had no idea that Nikon still sells them, but on reflection, I recall having been given to understand that Nikon still lists some number of manual focus lenses. So that seems reasonable. Neither the Nikon nor the Pentax "K" 50/1.2 is anywhere near as large as the current Canon, but I'd guess that, at least in part, has to do with the autofocus stuff. The other impression I've gotten from the current lot of Canon L glass is that some of that bulk may be what is required to get to the same level of robustness the older smaller metal lenses possessed. Oh, well... I've heard differing opinions about the Nikon 35/1.4; pros bought them up to use as fast normal lenses, but some say the 1.4 wasn't really worth the price premium. But then one hears/reads a lot of things if one persists long enough. My take on those ultrafast normals was that it was depth of field control that was more important than their low light capabilities. Which was part of what I was after with the Canon 1.2. I do know that the older Nikon 55/1.2 was not all that great a lens, at least the copy I have is not. The 50/1.2 is supposed to be a better design, though I must admit I'd not done enough with it to figure out how much better. The reality, I gather, is that there is enough variation between different copies of the same optics such that variation between different manufacturers is somewhat less relevant than one might suppose. In any case, at the end of the day, it's what sort of images one gets with any of this gear, and that's another story altogether. Longfellow >>> Yeah, I bought the 50/1.4 and the focus felt gritty and the autofocus >>> was noisy. For comparison, I've got copies of Nikon and Pentax 1.4s and [quoted text clipped - 29 lines] > worth the price premium. But then one hears/reads a lot of things if > one persists long enough. The 35mm f/2 manual focus is really excellent and smaller but the 1.4 is not huge and offers some real differences in ability. The 28mm f/2 is another great little manual lens, it focuses so close. > My take on those ultrafast normals was that it was depth of field > control that was more important than their low light capabilities. [quoted text clipped - 10 lines] > > Longfellow > The 35mm f/2 manual focus is really excellent and smaller but the 1.4 is > not huge and offers some real differences in ability. The 28mm f/2 is > another great little manual lens, it focuses so close. That's as I've been given to understand. Again, I know very little about Nikon optics, although I read user reports and opinions (like everyone else, I suppose). I'd still shoot film and enjoy all that great old gear; well, I still do on occasion, but not on a regular basis. Just often enough so that my polyglot collection gets off the shelf and out in the field. And of course, if one can't be young and beautiful, at least one can be cool with old kit that the young folk have never seen. Which means that old farts like myself are the only ones that appreciate what they see, and that's sad. Then there is B&W, and wet processes, and enlargers, and... Nah, I already have too much to do now. Which means I need to get off this forum and get busy. Thanks for the chat! Longfellow > But I guess I question the whole concept of "necessary > automation". I remember learning to shoot moving objects, birds, > people, and all that. It took some intelligent practice: how to move > one's body, how to follow focus, and all that. Sure, question. Question why you don't whistle your posting into the phone line. Question why you need a powerful PC when others used to get along with a teletype. Question why you don't build your own car and camera, as people used to do --- or why you don't use a horse for transportation. Question on. Just questioning the single bit you personally can do without is just proving you don't grasp the concept of "necessary automation" --- just ask someone with a pacemaker about it. And don't forget going back to film, too! -Wolfgang >> But I guess I question the whole concept of "necessary >> automation". I remember learning to shoot moving objects, birds, [quoted text clipped - 14 lines] > > -Wolfgang Have you figured out just what it was/is that you're trying to say? Longfellow >> Sure, question. Question why you don't whistle your posting >> into the phone line. > Have you figured out just what it was/is that you're trying to say? Yep. You belong in my kill file for reading disability. [x] Score adjusted. -Wolfgang > Gear: Canon 5D2, 24-105; 50/1.2; 100-400 zoom. Works well, compact, > etc. [quoted text clipped - 3 lines] > Biggest complaint was that it just wasn't that much sharper than the 1.4 > and cost a lot more. In general, I would not expect an f/1.2 lens to be as sharp as an f/1.4 lens, especially wide open, and especially at the edges. Consequently, you are going to have a harder time getting a lens to autofocus at the edges. All lenses are designed around a series of tradeoffs. Often that means that you have a choice: wider apertures or sharper focus. > As soon as I switched the autofocus mode back to the center point, the > misfocus problem disappeared. I concluded that the "all points active" > mode did indeed present the problem of unpredictable point of focus, and > that what was happening was that the autofocus system wasn't focusing > where the operator presumed it was. No wonder it wasn't sharp! As expected. Some of those systems work better than others, but none will work as well as the photographer actually choosing the point of focus. SignatureWaddling Eagle World Famous Flight Instructor [ . . . ] > So I've always used just the center focus point and made it my business > to use it thus. Focus and reframe: Like that's too much trouble and [quoted text clipped - 21 lines] > > What am I missing about all this? If there's anything you're missing, I'm missing it too. I never could see any great advantage to any sort of wide-area or multi-point AF, and to the best of my recollection *all* the serious AF misses I've ever had have been the result of using that sort of feature. Now I will say that most of those misses have been with compact cameras of various brands, including Nikon, while my Nikon DSLRs seem to be a lot smarter about selecting the best point to focus on. Still I don't really trust it. > [ . . . ] >> [quoted text clipped - 26 lines] > If there's anything you're missing, I'm missing it too. I never could see > any great advantage to any sort of wide-area or multi-point AF, It's mostly for tracking moving subjects. Also useful on a tripod where it's not convenient to re-frame although live view is more relevant there. > and to the > best of my recollection *all* the serious AF misses I've ever had have been > the result of using that sort of feature. Now I will say that most of those > misses have been with compact cameras of various brands, including Nikon, > while my Nikon DSLRs seem to be a lot smarter about selecting the best point > to focus on. Still I don't really trust it. >> [ . . . ] >>> [quoted text clipped - 29 lines] > It's mostly for tracking moving subjects. Also useful on a tripod where > it's not convenient to re-frame although live view is more relevant there. OK. That makes sense. I don't think I've seen that rationale given before. |
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