Moving to full frame...

matja · 3 Sep 2015 at 09:05

Just a mention that there is no difference in depth of field between sensor sizes, given the same subject distance, focal length and aperture. What a larger sensor can let you do, is get closer to the subject with the same focal length, which reduces the depth of field - but changes the perspective in the process.

eyetrip · 3 Sep 2015 at 10:19

Interesting.

From all the times I have seen people talking of full frame, I really got the impression that it allowed increased DOF.

It was not a consideration for me deciding to try full frame though. Mainly I was after better low light and high iso performance. Hopefully I am right that I should get those aspects out of going FF.

Biggest drawback for me is the crop of apsc on a decent sensor is good for getting "closer" to subject.

Looks like my A7 ii will only arrive Monday

the_director · 3 Sep 2015 at 19:03

Very happy with the A7ii so far, it does remind me how good the A6000 is, image quality wise. Lovely to have the true focal length of old lenses though.

The only issue so far - and it seems to be a common one - is that several of my lens adapters do not fit on the A7ii mount, but fit my A6000 fine. SOmething to do with slight change of tolerance on the lens mount i hear.

I'll need to try and find adapters sold as compatible with the A7ii now. luckily my FD adapter works and I can use that with my Adaptall lenses and FD lenses, however, my 28mm f1.9 Vivitar is OM, so all out of luck with that for the time being.

a1ex2001 · 4 Sep 2015 at 12:01

matja said:
Just a mention that there is no difference in depth of field between sensor sizes, given the same subject distance, focal length and aperture. What a larger sensor can let you do, is get closer to the subject with the same focal length, which reduces the depth of field - but changes the perspective in the process.

Which is a long winded way of saying if you take the same picture with full frame you'll get less dof!

squerble · 4 Sep 2015 at 19:04

If you have a crop camera, you multiply both the focal length and the aperture to get the 'equivalent' full-frame image. This means both field of view (FoV) and depth of field (DoF).

I saw a video that clearly showed the difference, a full frame camera shot at 200mm f/2.8 was then compared with a M4/3 (2x crop factor) at 100mm f2/.8. The field of view was the same in the two shots, but the background was noticeably sharper. The full frame camera was then shot at 200mm f/5.6 (2.8*2) and the results ended up the same.

Not to forget that the depth of field changes depending on the distance of the subject from the lens. If you take a picture close up to an object and focus on it, an f/1.8 or even wider at f/1.4 or f/1.2, the depth of field gets as thin as a sheet of paper

but if you took a picture of an object further away (or at least you focus on something further away) then that depth of field increases.

matja · 5 Sep 2015 at 13:29

a1ex2001 said:
Which is a long winded way of saying if you take the same picture with full frame you'll get less dof!

If you preserve angle of view (what you mean by "same picture"?) obviously you'll see a difference because the focal length must be changed, but only the lens determines depth of field.

If you take an image on a D800 and crop it to the size of a D7000 frame, the result is identical (apart from slight noise and colour differences) to what you'd get if you took the image on the D7000 (same sensor pixel pitch).