600 F5.6 DO

Started 2 months ago | Discussions thread
AKRover Regular Member • Posts: 224
Re: 600 F5.6 DO

H2ODoctor wrote:

I agree that is the best option now. However, a 600 DO would give even more reach. With a 1.4X, I could get to 840 mm and a 2X would give 1,200 for perched birds although I don’t imagine I would do that very often due Lack of light.

The amount of detail a lens delivers depends on its diameter, not its focal length. Focal length only determines how many pixels we get to keep when cropping to the AOV we desire, but we have remarkable pixel density. I can (and sometimes do) crop my 400DO to 2200mm with 5.4 megapixels on my M6II using only a 1.4X.  This ability to crop effectively turns my lens into a 900-2200f/9-22 zoom lens.  I could put a 2X on and get to the same 2200 with 10.8 megapixels, but I don’t really need that many pixels for small bird images and I would lose the option of shooting 900 without cropping. Your 600 proposal would get me to 2350 at 5.3 megapixels using the lens bare, or 10.6 megapixels with the 1.4X, or 21.2 megapixels with the 2X, but it really doesn’t let me go any tighter on the AOV because diffraction limits the amount of detail. In all of the crops described above, diffraction will look like f/22 equivalent (my personal limit for the purposes of calculations). 2350 is 7% more reach than the existing 400 DO’s 2200, but it would come at the expense of a physically much longer lens and the loss of f/4 as an option. That existing 400 DO is a nice compact way of getting 100mm of usable aperture (considerably better than Nikon’s 89mm 500PF). Is there a compelling case for Canon to give us 7% more reach in a less portable package? I don’t see it. A 500f/4 DO with 25% more aperture would certainly be more interesting.

Don't make the mistake of thinking sensor size has anything to do with reach.  Sensor size is essentially the limit on your widest AOV for your lens, not the tightest.  This all comes down to pixel density and aperture diameter.  Answer two questions for yourself and the calculations become easy.  How many pixels do you really need?  How much diffraction can you tolerate (I even shot a bird feather in studio while varying f-number)?  If you really think you would love a 600f/5.6, the 400 DO II already exists and is awesome.

 AKRover's gear list:AKRover's gear list
Canon EOS 5D Mark III Canon EOS 1200D Canon EF 50mm F1.8 II Canon EF 100mm f/2.0 USM Canon EF 200mm f/2.8L II USM +8 more
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