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Photo Forum / Digital Photography / DSLR Cameras / January 2008Megapixel war just beginning with DSLRs
Pentax K20D, 1.5 crop and 15 megapixels, now Sony?? I've got to admit, a 25 megapixel 1.5 crop camera would be hilarious. http://masterchong.com/v2/sony-alpha/sony-a300-and-a350-camera-body-photos.html > Pentax K20D, 1.5 crop and 15 megapixels, now Sony?? I've got to > admit, a 25 megapixel 1.5 crop camera would be hilarious. > > http://masterchong.com/v2/sony-alpha/sony-a300-and-a350-camera-body-p... I'd just like to add to this that there is (obviously) a pixel size at which the gains of resolution are outweighed by the losses in DR and sensitivity. So, what specifically can we say (given the performance we've seen with the latest DSLRs) is the smallest practical pixel size for a DSLR? >> Pentax K20D, 1.5 crop and 15 megapixels, now Sony?? I've got to >> admit, a 25 megapixel 1.5 crop camera would be hilarious. >> >> http://masterchong.com/v2/sony-alpha/sony-a300-and-a350-camera-body-p... > I'd just like to add to this that there is (obviously) a pixel size at > which the gains of resolution are outweighed by the losses in DR and > sensitivity. So, what specifically can we say (given the performance > we've seen with the latest DSLRs) is the smallest practical pixel size > for a DSLR? That only matters when legacy lenses are used. Lenses of higher precision can be made, and if sensors with smaller pixels come into use, better lenses will be made to exploit them.  SignatureChris Malcolm cam@infirmatics.ed.ac.uk DoD #205 IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK [http://www.dai.ed.ac.uk/homes/cam/] > I'd just like to add to this that there is (obviously) a pixel size at > which the gains of resolution are outweighed by the losses in DR and > sensitivity. So, what specifically can we say (given the performance > we've seen with the latest DSLRs) is the smallest practical pixel size > for a DSLR? 12M on an APS-size sensor (Nikon D2x) is quite demanding of lenses. It really shows when a lens is less than perfect, and benefits from using the best ones you can use. Smaller pixels will make this problem more significant -- but the problem can be solved by making better lenses. Another issue is that pixels that small make focus errors, camera shake, etc., that much more pronounced. This is worked around by better technique. The tricky one is that, at this size, you have a practical minimum aperture of f/11 before you start losing resolution to diffraction. With smaller pixels this will get worse, and I wouldn't want to use an APS-size camera that can't go below f/8. You can't really solve this one with better lenses. SignatureJeremy Nixon | address in header is valid (formerly jeremy@exit109.com) http://www.flickr.com/photos/100mph/ >> So, what specifically can we say ...is the smallest practical pixel size >> for a DSLR? [quoted text clipped - 4 lines] > an APS-size camera that can't go below f/8. You can't really solve > this one with better lenses. Interesting point. f/11 or 16 is where a 12MP D300 or D2x becomes diffraction limited so for 15MP maybe f/16 isn't worthwhile (for that type of tripod landscape/studio work anyways). > >> So, what specifically can we say ...is the smallest practical pixel size > >> for a DSLR? [quoted text clipped - 8 lines] > diffraction limited so for 15MP maybe f/16 isn't worthwhile (for that > type of tripod landscape/studio work anyways). Like Olympus, diffraction kicks in at around f8. >>>> So, what specifically can we say ...is the smallest practical pixel size >>>> for a DSLR? [quoted text clipped - 8 lines] > > Like Olympus, diffraction kicks in at around f8. I guess that's what large format is for... like a studio tabletop shot, you can ultimately stop down more if the subject holds still. I wonder what the '35mm equivalent f/stop' of a stitched pano would be? > I wonder what the '35mm equivalent f/stop' of a stitched pano would be? The same: stitching amounts to using a larger sensor with the same- sized pixels, if you think about it. The focal length and aperture diameter also don't change. >> I wonder what the '35mm equivalent f/stop' of a stitched pano would be? > > The same: stitching amounts to using a larger sensor with the same- > sized pixels, if you think about it. The focal length and aperture > diameter also don't change. OK yes, that makes sense, Doh. The DOF does increase though. > > I wonder what the '35mm equivalent f/stop' of a stitched pano would be? > > The same: stitching amounts to using a larger sensor with the same- > sized pixels, if you think about it. The focal length and aperture > diameter also don't change. But he was asking about the '35mm equivalent f/stop'. Since in effect we are using a much larger sensor the equivalent f/stop is smaller, poor DOF but very good resolution. But a easier way to look at it is your way, a large sensor at the same FL and f/stop that the photos to be stitched were taken at. In many ways stitching is like having a LF camera, great resolution but poor DOF. Scott >>> I wonder what the '35mm equivalent f/stop' of a stitched pano would be? >> The same: stitching amounts to using a larger sensor with the same- [quoted text clipped - 9 lines] > ways stitching is like having a LF camera, great resolution but poor > DOF. It would have more DOF on the print. Maybe the question was too strange to answer: the f/stop doesn't care about sensor size but the DOF matters. Let's see, if you take a 4/3 sensor & stitch 4 shots at 8mm f/3.5 that's going to make the equivalent of a 16mm field of view on full frame. But wouldn't it take something like f/5 for the same DOF? And the 8mm lens probably only stops down to f/8 (doubles to f/11 stitched) where the 16mm lens goes 2 more stops to f/22 and opens up another half stop to f/2.8. > >>> I wonder what the '35mm equivalent f/stop' of a stitched pano would be? > >> The same: stitching amounts to using a larger sensor with the same- [quoted text clipped - 18 lines] > probably only stops down to f/8 (doubles to f/11 stitched) where the > 16mm lens goes 2 more stops to f/22 and opens up another half stop to f/2.8.- Hide quoted text - 4 shots stitched, assume no overlap, witha 8mm lens will have the same field of view (or close to it) of a full frame camera with a 8mm lens. To look at this another way, I can use a 100mm lens on my camera to get the same FOV, using stitching, as one shot with a 25mm lens. If I want the same DOF in a print with the 100mm lens as the 25mm lens at say f/4 I would need to set the 100mm lens at f/16. Scott >>>>> I wonder what the '35mm equivalent f/stop' of a stitched pano would be? >>>> The same: stitching amounts to using a larger sensor with the same- [quoted text clipped - 24 lines] > want the same DOF in a print with the 100mm lens as the 25mm lens at > say f/4 I would need to set the 100mm lens at f/16. Ah, sorry I got it turned around. What about this: use the same full frame 16mm lens on a 2/3 camera & stitch to get the same thing, same f/stop. More pixels though so it's not much use to stop down more than f/8. But then it has more resolution so is sharper before stopping down excessively. >>> So, what specifically can we say ...is the smallest practical pixel size >>> for a DSLR? [quoted text clipped - 4 lines] >> an APS-size camera that can't go below f/8. You can't really solve >> this one with better lenses. > Interesting point. f/11 or 16 is where a 12MP D300 or D2x becomes > diffraction limited so for 15MP maybe f/16 isn't worthwhile (for that > type of tripod landscape/studio work anyways). Isn't worthwhile if using the full resolution. But if you have 12MP you might well be content with say a close-up product photograph of 3MP resolution, for which you could either use in-camera or editor resizing. In that case would you gain anything, such as increased DoF, by being able to stop down further than the 12MP diffraction limit? SignatureChris Malcolm cam@infirmatics.ed.ac.uk DoD #205 IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK [http://www.dai.ed.ac.uk/homes/cam/] >>>> So, what specifically can we say ...is the smallest practical pixel size >>>> for a DSLR? [quoted text clipped - 13 lines] > resizing. In that case would you gain anything, such as increased DoF, > by being able to stop down further than the 12MP diffraction limit? Yes there are going to be situations where it's useful: where you don't need a big print but do need the DOF. > Isn't worthwhile if using the full resolution. But if you have 12MP > you might well be content with say a close-up product photograph of > 3MP resolution, for which you could either use in-camera or editor > resizing. In that case would you gain anything, such as increased DoF, > by being able to stop down further than the 12MP diffraction limit? At 12MP APS-size, anything below f/11 loses resolution, but yes, you gain the expected DoF. The best example I have is this shot: http://www.flickr.com/photos/100mph/522280431/ I shot that at f/22 (Nikon D2x, 10.5mm) knowing I'd be losing resolution, but with the flower a couple inches from the lens, I needed the DoF. The resulting shot has about 6MP of useful resolution -- I can reduce the original to that size without losing any detail whatsoever. SignatureJeremy Nixon | address in header is valid (formerly jeremy@exit109.com) http://www.flickr.com/photos/100mph/ > > Isn't worthwhile if using the full resolution. But if you have 12MP > > you might well be content with say a close-up product photograph of [quoted text clipped - 18 lines] > (formerly jer...@exit109.com) > http://www.flickr.com/photos/100mph/ For static images, this program does a terrific job: http://www.heliconsoft.com/heliconfocus.html I couldn't believe it when I saw the result, I was sure it wouldn't work very well. Here's a macro sample at 50mm f4: http://www.pbase.com/andersonrm/image/92272575 How many people on this newsgroup wrote that APS-c sized sensors could never achieve the noise levels seen on the new Sony wunderkind in the D300 and new Sony dSLR? In truth most users of consumer grade dSLRs do not need more than 6mps. |
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