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Photo Forum / Digital Photography / DSLR Cameras / April 2006lens sharpness
iam now shooting a canon 20D would like to buy a 400 as the big boys are out of my wallet size iam looking at the canon 100-400 5.6 and the canon 400 5.6 I realize that the 100-400 might be a more all around lens then the stright 400 but will the zoom be as sharp at 400 as the stright 400? also will a canon 300 f4 auto focus with a 1.4 teleconverter ? thanks for any information that you can give. > iam now shooting a canon 20D would like to buy a 400 as the big boys are out > of my wallet size iam looking at the canon 100-400 5.6 and the canon 400 5.6 > I realize that the 100-400 might be a more all around lens then the stright > 400 but will the zoom be as sharp at 400 as the stright 400? also will a > canon 300 f4 auto focus with a 1.4 teleconverter ? thanks for any information > that you can give. All I know is the teleconverter will reduce f/stop & autofocus won't work plus teleconverters invariably only look their best stopped down some more. I got a 2xTC for a 70-200 because I wasn't planning to do much at that distance, but sometimes it's handy, especially in good light. What do you have now? > iam now shooting a canon 20D would like to buy a 400 as the big boys are out > of my wallet size iam looking at the canon 100-400 5.6 and the canon 400 5.6 > I realize that the 100-400 might be a more all around lens then the stright > 400 but will the zoom be as sharp at 400 as the stright 400? also will a > canon 300 f4 auto focus with a 1.4 teleconverter ? thanks for any information > that you can give. The 20D will autofocus up to f/5.6, so will with the 300 f/4 +1.4x. The 300 f/4 L IS is a sharp lens, and still sharp with a 1.4x. Example: http://www.clarkvision.com/galleries/gallery.bird/web/lorikeet.c04.07.2005.JZ3F8 962.b-700.html My 100-400 is not sharp at 400, so I would not recommend it. Others I know do have reasonably sharp 100-400 at 400, so if you decide on the 100-400 test the specific one before buying. But it is still not as sharp as fixed focal length lenses. The 400 f/5.6 is sharp and has a very fast autofocus (no IS) and is preferred by some bird photographers for hand held flight shots. The 400 f/5.6 will autofocus faster than the 300 f/4 +1.4x TC. I prefer IS lenses. I use the 300 f/4 + TC when I want to travel light, but prefer a 500 f/4. I use kenko pro 300 TCs and they work very well. Roger Photos at: http://www.clarkvision.com Roger have you tested the Kenko against the Canon converters? regards Don from Down Under >> iam now shooting a canon 20D would like to buy a 400 as the big boys are >> out [quoted text clipped - 26 lines] > Roger > Photos at: http://www.clarkvision.com > Roger > [quoted text clipped - 3 lines] > > Don from Down Under No I have not. But because I see almost no degradation when adding the TCs onto L lenses, I am completely satisfied with their performance. If I thought they were below canon TCs, I would have switched. Sometime when I'm in the field with other canon guys, I'll see if one will exchange TCs for a test. Roger SNIP >> have you tested the Kenko against the Canon converters? SNIP > No I have not. But because I see almost no degradation when adding > the TCs onto L lenses, I am completely satisfied with their > performance. If I thought they were below canon TCs, I would have > switched. There may be some differences between samples. I traded my 2x Kenko Pro 300 (because it lost too much contrast on my EF 200mm f/2.8) in for the Canon one. It's a huge improvement on that lens. Other lenses may interact differently. Bart In message <4437F9BC.3020702@qwest.net>, "Roger N. Clark (change username to rnclark)" <username@qwest.net> wrote: >No I have not. But because I see almost no degradation when adding >the TCs onto L lenses, I am completely satisfied with their >performance. If I thought they were below canon TCs, I would >have switched. Sometime when I'm in the field with >other canon guys, I'll see if one will exchange TCs for a test. I lost my Canon 1.4x and bought a Kenko Pro 300 to replace it. No regrets. Works with any lens (although short focal length lenses less than about 60mm get really soft at the edges with the 1.6x crop). For full-frame, they recommend 90mm and above, I believe.  Signature<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<> John P Sheehy <JPS@no.komm> ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>>< I haven't tried the Pro 300 1.4TC but did have the 2 times and have packed it up and sold it, as I find it very poor quality when used with my 400 5.6 (which as you know is pretty sharp) and man focused. Would be interested in other opinions about the two times as I may have not had the Pro 300, just cannot remember. I was thinking about buying a canon 2 times to go with the 1.4 but have just invested in a 90 mm macro (tamron) and a 25 - 105 IS Canon F4 so will be broke for a while. Thanks for the comments so far. regards Don from Down Under > In message <4437F9BC.3020702@qwest.net>, > "Roger N. Clark (change username to rnclark)" <username@qwest.net> [quoted text clipped - 11 lines] > full-frame, they recommend 90mm and above, I believe. > ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>>< >I haven't tried the Pro 300 1.4TC but did have the 2 times and have packed >it up and sold it, as I find it very poor quality when used with my 400 5.6 [quoted text clipped - 3 lines] >1.4 but have just invested in a 90 mm macro (tamron) and a 25 - 105 IS Canon >F4 so will be broke for a while. Thanks for the comments so far. Have you used other 2xes? I think people are too quick to blame TC issues on the TC, when in fact, the real problems are the main lens and technique, as well as unrealistic expectations. Think about extension tubes - they magnify images on the focal plane, much more than the lens was intended to do, by design. If the images you get with them are soft, what do you blame? It can be camera shake, low DOF, lack of MTF, aperture open more than usual to deal with light loss, etc. You can not blame the tubes, because there is nothing in them! In the same way, even a theoretically perfect TC can give dissapointing results. A 2x TC is going to reduce the pixel-to-pixel contrast on 99% of lenses. Your 400 f/5.6 is a very sharp lens, relative to the full line of lenses, but dull compared to the fastest 300mm, 400mm, and 500mm Canon IS L telephotos, especially at the same aperture. If you're going to zoom in at 100% on the monitor, you *will* see some loss. That is not the only way to view images, though. If the loss is minor, then you are still getting a better capture of the subject, at the same distance, than if you didn't use the TC, if you didn't compromise focus, DOF (more than you want), or too much shutter speed, because you are now over-sampling the subject, decreasing the size of pattern noises and demosaicing artifacts relative to the subject size. IOW, unless you go way into the soft zone, your 2x image will look better than the 1x one, both viewed at the same magnification. If you go too far into the soft zone, then you are just wasting photns with a TC. Signature<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<> John P Sheehy <JPS@no.komm> ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>>< >>I haven't tried the Pro 300 1.4TC but did have the 2 times and have packed >>it up and sold it, as I find it very poor quality when used with my 400 5.6 [quoted text clipped - 34 lines] > go too far into the soft zone, then you are just wasting photns with a > TC. I agree. A 2x on a 400 mm f/5.6 gives 800 mm focal length. On a 20D camera with 6.4 micron pixels, that works out to 1.6 arc-seconds/pixel. That is very difficult to keep steady. I have done stacked 1.4 and 2x (pro 300s) with a 500 mm f/4 L IS and 1D Mark II (8.2 micron pixels). The limit, even with IS is steadiness. Examples: Moon: http://www.clarkvision.com/galleries/gallery.astrophoto-1/web/moon-JZ3F3658-60-c -5x-700.html Bears: http://www.clarkvision.com/galleries/gallery.bear/index.html Roger >Think about extension tubes - they magnify images on the focal plane, >much more than the lens was intended to do, by design. If the images >you get with them are soft, what do you blame? It can be camera shake, >low DOF, lack of MTF, aperture open more than usual to deal with light >loss, etc. You can not blame the tubes, because there is nothing in >them! You overlook the fact that lenses are computed to minimise aberrations at a certain set of object/image distances. Spherical aberration, field flatness and other degradations can rise (slowly or rapidly depending on design) as you move too far away from these conjugates. This is why dedicated macro lenses give much better results at high magnifications. So you can (under these circumstances) blame the tube, for moving the lens too far out of its "comfort zone". Of course, your other cogent comments may also apply. David SignatureDavid Littlewood >>Think about extension tubes - they magnify images on the focal plane, >>much more than the lens was intended to do, by design. If the images >>you get with them are soft, what do you blame? It can be camera shake, >>low DOF, lack of MTF, aperture open more than usual to deal with light >>loss, etc. You can not blame the tubes, because there is nothing in >>them! >You overlook the fact that lenses are computed to minimise aberrations >at a certain set of object/image distances. No, I didn't "overlook" that at all. I made an analogy to extension tubes, as another example of forcing a lens to do what it isn't made to do, and to illustrate by contrast that it isn't necessarily the glass in the TC that causes the degradation of the 100% pixel view. "Not mentioned" does not equal "overlooked". Signature<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<> John P Sheehy <JPS@no.komm> ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>>< >>>Think about extension tubes - they magnify images on the focal plane, >>>much more than the lens was intended to do, by design. If the images [quoted text clipped - 12 lines] > >"Not mentioned" does not equal "overlooked". It may, of course, in the eye of the beholder. SignatureDavid Littlewood >It may, of course, in the eye of the beholder. Only if it's relevant in context. Signature<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<> John P Sheehy <JPS@no.komm> ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>>< >I haven't tried the Pro 300 1.4TC but did have the 2 times and have >packed it up and sold it, as I find it very poor quality when used >with my 400 5.6 (which as you know is pretty sharp) and man focused. >Would be interested in other opinions about the two times as I may >have not had the Pro 300, just cannot remember. I had the Pro 300 2x and sold it to get the Canon one for use on my 200mm. It is a world of difference! Maybe it's a quality control thing for the Kenko, as Roger seems happy with his copy. Bart Thanks all. What I was trying to ascertain was the quality difference in the 2X Kenko (which I have used) and a Canon 2x. Obviously the other comments may hold for all converters (ie, magnification issue, pixel issues and stability) but the issues of the glass and construction differences etc are what I was more focused on (no pun intended). I get good results with my Canon 1.4 all things considered, poor results with the Kenko 2X. regards Don >>I haven't tried the Pro 300 1.4TC but did have the 2 times and have packed >>it up and sold it, as I find it very poor quality when used with my 400 [quoted text clipped - 7 lines] > > Bart >Thanks all. What I was trying to ascertain was the quality difference in >the 2X Kenko (which I have used) and a Canon 2x. Obviously the other >comments may hold for all converters (ie, magnification issue, pixel issues >and stability) but the issues of the glass and construction differences etc >are what I was more focused on (no pun intended). I get good results with >my Canon 1.4 all things considered, poor results with the Kenko 2X. The way I just read what you wrote, you still have no idea how good a 2x your Kenko 2x is. I have a Tamron SP 2x, which is a re-badged Kenko Pro 300, and it gives good results for a 2x and the lenses I have; I'm happier with the shots I can get in decent light than shooting the same subject at the same distance, without the TC. I have heard a lot of complaints about the Canon 2x; that could either be optical problems relative to other 2x converters, or just unrealistic expectations. I don't think that many people are really capable of giving an objective statement about 2x converters, because they ignore the fact that the MTF *HAS* to drop with a TC; that is inevitable and should be expected. You also need more light to use a 2x TC; you lose two stops from the magnification, you may need to halve the exposure time (maybe 1/3 at the IS limit, with IS), you may need to stop down from full aperture to be sharp enough to warrant the TC with some lenses; it can all wind up costing you 3 to 4 stops in the worst cases, to be worthwhile. The viewfinder is darker, too; guaranteed. AF, even if you force it, is harder with the 2x than without a TC or with a 1.4x, and manual focus becomes more critical as the DOF drops, as the lens is designed to be focused with a tolerance with a given DOF in mind. Signature<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<> John P Sheehy <JPS@no.komm> ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>>< In message <44373491.2060008@qwest.net>, "Roger N. Clark (change username to rnclark)" <username@qwest.net> wrote: >My 100-400 is not sharp at 400, so I would not recommend it. >Others I know do have reasonably sharp 100-400 at 400, so if >you decide on the 100-400 test the specific one before buying. Here's a 100% crop from mine, with 2.8x worth of TCs stacked (1120mm, at close range (f/16 in EXIF, but actually f/22 because camera ignores 1.4x TC). The subject is printed text on paper. http://www.pbase.com/image/58365468 The left and right edges of text are softer because they are out of focus. Paper was shot at an angle so *something* would be in focus. Image equally sharp at edges where in focus. I show it this way, because I don't want the sensor to be the limiting factor. This way, it is clearly the lens (and to a lesser extent, the TCs). In my experience, the closer the better with this lens. Signature<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<> John P Sheehy <JPS@no.komm> ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>>< >iam now shooting a canon 20D would like to buy a 400 as the big boys are out >of my wallet size iam looking at the canon 100-400 5.6 and the canon 400 5.6 >I realize that the 100-400 might be a more all around lens then the stright >400 but will the zoom be as sharp at 400 as the stright 400? also will a >canon 300 f4 auto focus with a 1.4 teleconverter ? thanks for any information >that you can give. Have at it! http://www.photodo.com/nav/prodindex.html > iam now shooting a canon 20D would like to buy a 400 as the big boys are out > of my wallet size iam looking at the canon 100-400 5.6 and the canon 400 5.6 > I realize that the 100-400 might be a more all around lens then the stright > 400 but will the zoom be as sharp at 400 as the stright 400? also will a > canon 300 f4 auto focus with a 1.4 teleconverter ? Alternatives: Canon 70-300/4-5.6 IS + Olympus 1.45x Canon 200/2.8 + 2x http://digitcamera.tripod.com/#slr |
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