p.1 #1 · Does the crop mode on A7R III give me more depth of field?
Hello,
I'm wondering about the following: is the crop mode function on the A7R III taking just a part of the original shot, or is it an actual cropped sensor shot? I'm asking because I'm looking for more depth of field. I bought the A7R III specially to be able to get even more out of my 200-600 because I can crop it and still have enough to work with.
Owning also an Olympus OM-D E-M 1 II (2.0 crop) with 60 mm (mostly for macro) I know how handy the extra depth of field is. And I miss the focus stacking and pre-capture options in Sony!
Thanks in advance for your input!
Mar 21, 2020 at 07:55 AM
Steve Spencer Offline • • • • • • • Upload & Sell: On
p.1 #2 · Does the crop mode on A7R III give me more depth of field?
Theo Voorbij wrote:
Hello,
I'm wondering about the following: is the crop mode function on the A7R III taking just a part of the original shot, or is it an actual cropped sensor shot? I'm asking because I'm looking for more depth of field. I bought the A7R III specially to be able to get even more out of my 200-600 because I can crop it and still have enough to work with.
Owning also an Olympus OM-D E-M 1 II (2.0 crop) with 60 mm (mostly for macro) I know how handy the extra depth of field is. And I miss the focus stacking and pre-capture options in Sony!
The crop mode uses the pixels from the central part of the image, but it is the same as you would get if you cropped in post. Such a shot will have more apparent DOF, because you are magnifying the image, but it won't have more depth of field than using the equivalent focal length with the full sensor and stopping down the aperture. So if you are using a 24mm lens and the crop mode you will end up on your camera with a shot that looks a lot like a 35mm lens stopped down about a stop further. The crop mode will have less pixels and reduced dynamic range, however, so if you can use an equivalent lens at the longer focal length you won't pay the price of reduced resolution and dynamic range of using the crop mode.
Of course, in your situation cropping a 600mm image, using a longer focal length lens there are not a lot of options. You might get a better image by using a teleconverter than by cropping, but both methods degrade the IQ in different ways and you would have to do careful tests to decide which is better. When you are actually shooting things may be unfolding too fast to put on the teleconverter as well leaving cropping or crop mode as the only option.
p.1 #3 · Does the crop mode on A7R III give me more depth of field?
The larger DOF you get from μ43 is a product of using a shorter lens.
That is:
The DOF of a 25mm f/1.4 on μ43 = the DOF 32mm f/1.8 on APS-C = the DOF of 50mm f/2.8 on FF.
All of those are the result of having the same size physical aperture size of 17.86mm.
But if you're shooting the same focal length and aperture (600mm f/6.3), your DOF is going to be effectively/nearly the same (with some caveats about magnification, etc.).
You'd only get a larger DOF if you were using a 400mm f/6.3 on APS-C relative to the 600mm f/6.3 on FF.
p.1 #4 · Does the crop mode on A7R III give me more depth of field?
Thanks for your input! I'm not that technical I'm afraid but if I'm understanding correctly buying a Sony APS-C body with my 200-600 mm would give me more depth of field than using the crop mode function on the FF body?
p.1 #5 · Does the crop mode on A7R III give me more depth of field?
How the crop is made doesn't matter. Normally when cropping people display the final image at the same size so cropping is the same as magnifying the image. Magnifying blur decreases the depth-of-field.
If you want more depth-of-field you need to use a smaller aperture.
Mar 22, 2020 at 06:19 AM
Steve Spencer Offline • • • • • • • Upload & Sell: On
p.1 #6 · Does the crop mode on A7R III give me more depth of field?
Theo Voorbij wrote:
Thanks for your input! I'm not that technical I'm afraid but if I'm understanding correctly buying a Sony APS-C body with my 200-600 mm would give me more depth of field than using the crop mode function on the FF body?
No it will not. Using the crop mode on a FF camera will give you exactly the same DOF as using an APS-C body.
p.1 #7 · Does the crop mode on A7R III give me more depth of field?
The one way using crop mode or an ApS-C camera will give you more depth of field than using the full frame sensor (all of it) with the 200-600 is if you aren't focal length limited. So, for instance, if you could fill the framing you want at 600mm on full frame, and took a shot at 6.3, then entered crop mode or swapped for an APS-C body, now you'd have to adjust the focal length to 400mm to get the same framing. As such, at f/6.3, you'd end up with the same image, but with a bit more than one stop extra depth of field.
If you're shooting small birds, and are going to crop to APS-C size or smaller at 600mm, your depth of field will be identical between the two cameras or modes, because your focal length, position and such are the same.
As mentioned above, the greater depth of field on smaller sensors is due to using longer focal lengths for the same framing and same position on the full frame sensor, and shorter focal lengths with the crop sensor or mode.
p.1 #8 · Does the crop mode on A7R III give me more depth of field?
Thanks for your input! I'm not that technical I'm afraid but if I'm understanding correctly buying a Sony APS-C body with my 200-600 mm would give me more depth of field than using the crop mode function on the FF body?
No buying a Sony APS-C body with a hypothetical 133-400mm f/6.3 lens would give you more depth of field as your 200-600mm lens. It's the lens and its aperture that changes the depth of field on a smaller sensor, not the sensor itself.
Mar 22, 2020 at 09:57 AM
osv2 Offline • • • • [X]
p.1 #9 · Does the crop mode on A7R III give me more depth of field?
Theo Voorbij wrote:
Owning also an Olympus OM-D E-M 1 II (2.0 crop) with 60 mm (mostly for macro) I know how handy the extra depth of field is.
no format has "extra depth of field"
the defining point is when diffraction is noticeable, which happens with all sensor sizes when the actual dof is the same.
"Typically, the effects of diffraction softening do not even begin to become apparent until f/11 on FF (f/7.1 on APS-C and f/5.6 on mFT -- 4/3), and start to become strong by f/22 on FF (f/14 on APS-C and f/11 on mFT -- 4/3). By f/32 on FF (f/22 on APS-C, f/16 on mFT -- 4/3) the effects of diffraction softening are so strong that there is little difference in resolution between systems, regardless of the lens, sensor size, or pixel count." http://www.josephjamesphotography.com/equivalence/light.htm#diffraction
p.1 #11 · Does the crop mode on A7R III give me more depth of field?
Valner wrote:
.... why not change the aperture to get the DOF you want?
I get that of course but it's not always an option depending on the circumstances.
But from what I read it's the only solution until Sony comes up with focus stacking too.
p.1 #12 · Does the crop mode on A7R III give me more depth of field?
osv2 wrote:
no format has "extra depth of field"
the defining point is when diffraction is noticeable, which happens with all sensor sizes when the actual dof is the same.
"Typically, the effects of diffraction softening do not even begin to become apparent until f/11 on FF (f/7.1 on APS-C and f/5.6 on mFT -- 4/3), and start to become strong by f/22 on FF (f/14 on APS-C and f/11 on mFT -- 4/3). By f/32 on FF (f/22 on APS-C, f/16 on mFT -- 4/3) the effects of diffraction softening are so strong that there is little difference in resolution between systems, regardless of the lens, sensor size, or pixel count." http://www.josephjamesphotography.com/equivalence/light.htm#diffraction
Thanks for the input! I'll copy your part of diffraction on a note to put in my bag. I knew about it, but never realized the differences in formats. It's something to keep in mind. Especially for my 4/3 camera it's important. I will study your link too!
Mar 22, 2020 at 02:20 PM
osv2 Offline • • • • [X]
p.1 #13 · Does the crop mode on A7R III give me more depth of field?
there are some focus stacking options, but i've never tried it:
p.1 #14 · Does the crop mode on A7R III give me more depth of field?
I think I finally get where I was confused.
I will get more depth of field when using a 300mm on a Olympus 4/3 than with a 600mm on a FF Sony, both being on a 600 mm field of view. Not from using the same mm lens on different formats.
Mar 22, 2020 at 02:30 PM
osv2 Offline • • • • [X]
p.1 #15 · Does the crop mode on A7R III give me more depth of field?
Theo Voorbij wrote:
I think I finally get where I was confused.
I will get more depth of field when using a 300mm on a Olympus 4/3 than with a 600mm on a FF Sony, both being on a 600 mm field of view. Not from using the same mm lens on different formats.
so all you'd have to do is stop the ff lens down to f/8 to get the same dof.
remember, "all systems suffer the same amount of diffraction softening equally at the same DOF"... you can select f/22 on the oly 300/4, but that would have the same dof/diffraction as 600/44 on ff :-0
nobody in their right mind wants to use f/44 on ff.
p.1 #16 · Does the crop mode on A7R III give me more depth of field?
Theo Voorbij wrote:
I think I finally get where I was confused.
I will get more depth of field when using a 300mm on a Olympus 4/3 than with a 600mm on a FF Sony, both being on a 600 mm field of view. Not from using the same mm lens on different formats.
If they're both set to the same f-number, yes. If you stop down the 600m two stops compared to the Olympus, they'll be identical again.
so all you'd have to do is stop the ff lens down to f/8 to get the same dof.
remember, "all systems suffer the same amount of diffraction softening equally at the same DOF"... you can select f/22 on the oly 300/4, but that would have the same dof/diffraction as 600/44 on ff :-0
nobody in their right mind wants to use f/44 on ff.
I should have added "at the same aperture". Thanks for sharing the link to the DOF calculator. It confirms my problem not getting the whole bird in focus at 5 meters. With the virus going on I will have a lot the read and get into this week!
p.1 #19 · Does the crop mode on A7R III give me more depth of field?
Bringing this question back just in case.
So an a7riii with a 35mm f1.8 lens in aps-c/s35 mode will shoot like a 52.5mm focal equivalent at f2.8 depth of field equivalent if the subject is in the same place right?
Ex:
The image will look the same in terms of composition and depth of field with subject in the same exact location from the camera:
-An a7riii (in aps-c mode) + 35mm f1.8
-An a7riii (in FF mode) using a 52.5mm f2.8 lens (theoretical lens).
p.1 #20 · Does the crop mode on A7R III give me more depth of field?
Theo Voorbij wrote:
Thanks for your input! I'm not that technical I'm afraid but if I'm understanding correctly buying a Sony APS-C body with my 200-600 mm would give me more depth of field than using the crop mode function on the FF body?
Using 1.5x crop mode on an FF camera is identical to using an APS-C camera in every way including depth of field. An FF camera in 1.5x crop mode IS an APS-C camera.
