Is FF sensors going to slowly phase out?

Started Apr 11, 2013 | Discussions thread
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Re: Is FF sensors going to slowly phase out?
In reply to Erik Magnuson, Apr 12, 2013

Erik Magnuson wrote:

EinsteinsGhost wrote:

Yep. When your desire is to eliminate OOF areas, there is no need to smoothen out OOF areas.

Those who argue "the STF is purely for bokeh" would say otherwise.  You can rarely completely eliminate OOF areas for most 3D scenes and DOF depends on enlargement.   As the lens markings suggest, the special STF capability is only supported for widest apertures.

STF advantage is in bokeh. But that doesn't mean the lens isn't designed to be used at anything but wide open aperture.

Shallow DoF can often be an issue with longer FL. In fact, even with just 200mm f/2.8 that I use on my APS-C cameras, I have to stop down to f/4-f/5.6 (sometimes f/8) to get a reasonable DOF.

Bird photography is quite popular in this area. I know several people who shoot the 500mm f/4. If I ask them why the 500mm f/4, they say "all the above" (lower light, higher shutter speeds, and DOF control.)

I'm sure they would also want it to be lighter, smaller and deliver high IQ. When you see f/4 or f/2.8 on such long FL lenses, don't assume the thought process begins with "we want the shallowest possible DoF". It has to do with speed (which helps in lower light, for higher shutter speed). And that also extends to use of teleconverters.

Let me give you an example. At 100 ft, 500mm f/4 on FF will have a DOF of about 2.8 ft. Now, attach a 1.7X TC to that lens. With 850mm f/6.8, now you have a shallower DOF (about 1.6 ft). What do you think is more important for most photographers at this point? Getting a shallower DOF, or getting concerned about loss of AF speed (most DSLRs will lose peripheral PDAF points at this aperture) and loss of shutter speed (only to be made up by increasing ISO)?

The ability to control DOF doesn't imply always minimizing DOF. In fact, when using the STF, I strive to create a balance between shallow DoF and maximizing focus on my subject, to create isolation. Even this may or may not be always desirable (for example, if you want to blend-in the subject with the foreground and/or background with very little in focus.

Even sitting several rows back at an NBA game, may be about 60-70 ft from the nearest basket, with my NEX-3 and 200mm f/2.8, I'm looking at a DOF that is barely 4 ft. Substitute with 300mm f/2.8 and the DoF shrinks to barely more than the size of the basketball (about 1.5 ft).

Ever shoot with a SI photographer at a football game? I've assisted at a few.  Why do they use the 300mm or 400mm f/2.8 even for daylight games?  Simple: DOF control.  Shooting from the sidelines means the stands (or opposite sideline) are in the background.  Yeah, getting the focus spot-on with shallow DOF is tough, but that's why they get the big bucks.

They use 300mm f/2.8 for the same reason I would use 200mm f/2.8 on my APS-C. In fact, there is often a need for even greater need, hence even longer FL. The last thing one needs to worry about at these FL on pretty much any sensor is lack of DOF. The priority is reach, and speed. Not DOF control (which isn't a tall order at telephoto focal lengths).

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