[cali92rs]

No, some dude on here awhile ago had a bunch of spread sheets proving that FF had both shallower DoF but more DoF based on some crazy spreadsheets someone cooked up. Something to do with the level of magnification you need to make APS-c the same size as FF. It was total hogwash. But even saying more control is somewhat problematic. If you have the same number of F stops on two lenses you have the same amount of control. You may not have the same level of control in the shallow end, but that's different from having more control all together. Obviously, an APS-c at at f 32 in the long end has more DoF than an FF using the equivalent F0V. There isn't more control in one or the other it's just shifted a bit towards more DoF, away from shallow DoF.

I think technically you are correct...
But I also think people are more likely to shoot wide open than at the smallest aperture available. Plus it is nice to step down to say f4.0 to get some sharpness and still have shallow DOF for subject isolation.

[normhead]

I think technically you are correct...
But I also think people are more likely to shoot wide open than at the smallest aperture available. Plus it is nice to step down to say f4.0 to get some sharpness and still have shallow DOF for subject isolation.

I'm in agreement there to some degree. There is a whole shooting style based on narrow DoF, but if you look at the work of Diane Arbus or Richard Avedon you'll see there are also photographers who maximize DoF on the majority of their images. I still think of wide aperture as being more useful for low light, often the shallow DoF is a tolerated side effect. Personally I would suggest if you're shooting APS-c and you don't own any 1.4 lenses, you're probably not a candidate for FF based on your preference for shallow DoF. If you haven't bought a single lens that will give you the shallowest DoF on APS-c, it's pretty hard to argue you'll want it on FF.

On the other hand if your a fan of Stieglitz and many of the other champions of subject isolation through shallow DoF, you might want to go straight to FF to see if will meet your needs, before jumping straight into MF. If that's your style, dabbling in APS-c is probably a waste of your time.

[thibs]

No, some dude on here awhile ago had a bunch of spread sheets proving that FF had both shallower DoF but more DoF based on some crazy spreadsheets someone cooked up. Something to do with the level of magnification you need to make APS-c the same size as FF. It was total hogwash. But even saying more control is somewhat problematic. If you have the same number of F stops on two lenses you have the same amount of control. You may not have the same level of control in the shallow end, but that's different from having more control all together. Obviously, an APS-c at at f 32 in the long end has more DoF than an FF using the equivalent F0V. There isn't more control in one or the other it's just shifted a bit towards more DoF, away from shallow DoF.

All these talks about DOF are funny 'cos most of us don't print much and do not watch on big screens.
Since DOF is dependent on CoC and as such, depedent on the size the image is viewed...

All this is very... academic

[jsherman999]

No, some dude on here awhile ago had a bunch of spread sheets proving that FF had both shallower DoF but more DoF based on some crazy spreadsheets someone cooked up. Something to do with the level of magnification you need to make APS-c the same size as FF. It was total hogwash. But even saying more control is somewhat problematic. If you have the same number of F stops on two lenses you have the same amount of control. You may not have the same level of control in the shallow end, but that's different from having more control all together. Obviously, an APS-c at at f 32 in the long end has more DoF than an FF using the equivalent F0V. There isn't more control in one or the other it's just shifted a bit towards more DoF, away from shallow DoF.

That's true. In effect though, things reach hyperfocal quickly enough with a lot of lenses that the 'more control' at f/22 is sometimes only academic.

[normhead]

I think technically you are correct...
But I also think people are more likely to shoot wide open than at the smallest aperture available. Plus it is nice to step down to say f4.0 to get some sharpness and still have shallow DOF for subject isolation.

All these talks about DOF are funny 'cos most of us don't print much and do not watch on big screens.
Since DOF is dependent on CoC and as such, depedent on the size the image is viewed...

All this is very... academic

Ya, most of us just peer through the viewfinder and shoot. I bracket, and change apertures so I have a choice of DoF in the final image, but using a 2.8 lens, it's very rare my first choice of image is 2.8. For me, I'd say 25% of my images are at 5.6 , 45% at F8 at 15% at F 11, with the last 10% scattered from 2.8-4 and F16-32.

That's true. In effect though, things reach hyperfocal quickly enough with a lot of lenses that the 'more control' at f/22 is sometimes only academic.

Complicated by the theory of smaller pixel size being more prone to diffraction. I've yet to have take a useful F32 image on APS-c while I'm guessing that with a D600 and less diffraction limited pixel size you might be able to get a useful F 32 image... we do have F22 images that were best of their group shooting everything from F 2.8 to F 32...on APS-c.. but F22 may be the practical limit on a K-5 for preserving IQ. I have absolutely no plans to concoct a theory as to why that might be true. It's an observation based on image selection from various photo shoots.

SO maybe that should be revised to say you have as much control on APS-c as long as your lens doesn't close to smaller than F22. If it closes to f32, diffraction may be catching up with APS-c, where with larger pixels in a D600, f32 might still be useful. There are so many complicating factors, is it true for wide angle and telephoto? etc, that it hurts my brain just to think about it. Much easier to just shoot at a variety of F stops and select after.

[Hegemon]

Hey guys,

Not sure if this has been mentioned before but if you need a DOF calculator on the go and have an Android phone, this app might come in handy and it's free (they prob have them for iOS too):
https://play.google.com/store/apps/details?id=jds.dofcalc&feature=search_res...y5kb2ZjYWxjIl0.
https://play.google.com/store/apps/details?id=jds.dofcalc&feature=search_result#?t=W251bGwsMSwyLDEsImpkcy5kb2ZjYWxjIl0.

just go on google play store and search for DOF or photo tools....etc...plenty of choices out there. Thought it's an awesome app and it's all from the convenience of your phone

[Grega]

Hello everyone here is another DOF Calculator: Online Depth of Field Calculator.

[Rondec]

Yes, you're going to be at the mercy of any lenses' MFD on any format, but if you're shooting that close-in don't you usually want more DOF? Especially for macro? I feel like this ^^ is an academic limitation, but maybe you have need for less DOF at very close distances for something I'm not thinking of.

Norm was not happy with the close-focusing of that 50mm, but do you really need to get closer than this for non-macro situations? (note: that's not even MFD)



.
I think for me it's usually about subject isolation at distances more like:





.

Honestly, Jay, I feel like any of these photos is reproducible on APS-C. Maybe using a different focal length, from a different location, but it isn't that hard to take a photo of your kids with the background blurred out.

This was taken with the FA 31 at f2.8 and has relatively narrow depth of field for my taste. Could you make it more narrow on full frame? Sure, but to what point?

[jsherman999]

Honestly, Jay, I feel like any of these photos is reproducible on APS-C. Maybe using a different focal length, from a different location, but it isn't that hard to take a photo of your kids with the background blurred out.

It's harder on aps-c. You can't really know unless you either compare the formats directly with side-by-side shots, or if you have a lot of iterations with each. With that baby shot, a 35mm would have given me the same FOV on aps-c, but even wide-open at f/1.8 it would have had about 1.3 more stops of DOF, which would have defined the background more, made the subject 'float' just a little less, bringing the crap on the floor to the attention of the viewer a bit more. The whole image loses a small amount of 'specialness', and sometimes those small differences matter. Heck, if small differences didn't matter Zeiss and Leica (and probably the Limiteds) wouldn't exist.

It's not drastic, it's subtle, but it's real and the more you shoot with both formats the more you see it. You can think of it this way - if your 31ltd remained an f/1.8 lens with regard to exposure but was magically transformed into an f/2.8 lens with regard to DOF, would it matter to you? Not a lot, maybe, but you would notice it and you probably wouldn't welcome it after a while. You'd lose a small amount of DOF control.

This was taken with the FA 31 at f2.8 and has relatively narrow depth of field for my taste. Could you make it more narrow on full frame? Sure, but to what point?

I guess you'd just have to try it to know for sure. With FF, maybe shooting the 43ltd, you'd have been able to bracket DOF quite a bit there and choose the one that 'popped' the most for you. The 43ltd would have given you about that FOV (a tad wider) and DOF at f/4.5, which gives it some blistering sharpness on the plane of focus as well. I think the 43ltd on FF at f/2.8 would have been best, though - about a stop less DOF than your shot, background just a bit more diffused, subject floating, still very sharp at focus point.

Even if you don't agree, it would be nice to have the option, no?

.

[Rondec]

It's harder on aps-c. You can't really know unless you either compare the formats directly with side-by-side shots, or if you have a lot of iterations with each. With that baby shot, a 35mm would have given me the same FOV on aps-c, but even wide-open at f/1.8 it would have had about 1.3 more stops of DOF, which would have defined the background more, made the subject 'float' just a little less, bringing the crap on the floor to the attention of the viewer a bit more. The whole image loses a small amount of 'specialness', and sometimes those small differences matter. Heck, if small differences didn't matter Zeiss and Leica (and probably the Limiteds) wouldn't exist.

It's not drastic, it's subtle, but it's real and the more you shoot with both formats the more you see it. You can think of it this way - if your 31ltd remained an f/1.8 lens with regard to exposure but was magically transformed into an f/2.8 lens with regard to DOF, would it matter to you? Not a lot, maybe, but you would notice it and you probably wouldn't welcome it after a while. You'd lose a small amount of DOF control.



I guess you'd just have to try it to know for sure. With FF, maybe shooting the 43ltd, you'd have been able to bracket DOF quite a bit there and choose the one that 'popped' the most for you. The 43ltd would have given you about that FOV (a tad wider) and DOF at f/4.5, which gives it some blistering sharpness on the plane of focus as well. I think the 43ltd on FF at f/2.8 would have been best, though - about a stop less DOF than your shot, background just a bit more diffused, subject floating, still very sharp at focus point.

Even if you don't agree, it would be nice to have the option, no?

.

I actually do agree. My prime lenses except for my DA 15 are all full frame compatible and I would be glad to have it available, I just think the need for narrow depth of field is generally over stated. Content, composition, and light give photos impact long before depth of field does. The reality if you took most of my photos and gave them one stop less depth of field, they would still be crappy snapshots that had meaning to me, but not to anybody else (cause they are of my family).

[goubejp]

On the other hand, with long tele lenses, we have always too narrow depth of field. A 600F4 is hardly usable wide open cause depth of field is so narrow...

[Ash]

The benefit of FF largely comes from the thin DoF possible at around the 35-135mm range, where top lenses have maximum apertures of f/1.4 and f/1.8
Even at a stop down from maximum, where the lenses are considerably sharper and have excellent contrast, you will have effectively a one stop advantage in DoF control on a FF camera. As Jay says, this may not mean much to most photographers, but the difference is real and it matters significantly to those who use those critically wide apertures.

[Uluru]

The benefit of FF largely comes from the thin DoF possible at around the 35-135mm range, where top lenses have maximum apertures of f/1.4 and f/1.8...

Gosh,
I'm not sure what people are talking about here? You are turning things upside down.
Using the same focal length(*) and the same aperture, and a subject at the same distance, an APS-C camera will produce a thinner DoF than an FF camera.
In fact, using an FF is ways easier for a user to get OoF effects, and focus more accurately, because FF delivers more DoF to see which things are in fact in focus. It allows us to see more clearly.

From the DoF calculator: subject is 10 ft away, focal length is 50mm, aperture is f1.4.

An APS-C camera calculation:

Depth of field
Near limit = 9.67 ft
Far limit = 10.4 ft
Total = 0.68 ft
In front of subject 0.33 ft (48%)
Behind subject 0.35 ft (52%)

An FF camera calculation:

Depth of field
Near limit = 9.52 ft
Far limit = 10.5 ft
Total = 1.02 ft
In front of subject 0.48 ft (47%)
Behind subject 0.54 ft (53%)

1.02/0.68 = (voila!) 1.5

So, the data loudly says: we can focus more easily with an FF because it gives us 1.5 times more DoF!

And that is why many enthusiasts want an FF camera and switch systems to buy an FF from Nikon and Canon – it is easier to get acceptably focused photographs with an FF camera (as much as 50% more)! Simple as that. But what they don't get, or understand, is that Pentax does not have a "much worse" AF than Nikon and Canon — not at all — but an FF camera by default gives more focusing flexibility (and bigger VF) and more room for error!

Say D800, it does not have a "magical AF algorithm" — but just because it is an FF, it gives us more acceptable results than even a D7000 with an equally good AF system.

We are fooling ourselves. They some people tout Nikon and Canon's FF cameras have soooo much more precise AF than poor old Pentax. Yeah, right. Not true at all. Data shows that in the APS-C arena, a K5II can deliver as much good AF results as the 7D or D7000. Multiply that by 1.5, and a possible FF from Pentax will have "magically better AF", even if Pentax does nothing about it.

PS. Pentax only needs to improve tracking and predictability algorithms (a different game altogether), and if they do that, the next Pentax FF will blow your pants off.
PPS. (*)As Dof calculator suggests, used is the actual focal length of the lens for depth of field calculations.

[bxf]

Everything changes when you reposition the camera so that image size/FOV are the same.

[Uluru]

Everything changes when you reposition the camera so that image size/FOV are the same.

Yes, and light will change too, together with Earth's position on its orbit around the Sun.
So what is your point exactly? People don't use lenses as per your statement above; they use them same way as always, and complain about results. And switch systems.