Advantages of FF?!

Hi guys.

I would like to ask you guys about the advantages of FF against a Crop body.

What is obvious for me:
- Larger pictures
- Better Image quality.
- Less ISO noise

But there is one thing I cannot really get...

"Better background seperation"

Does anyone have a good example on this?!
FF vs. Crop.

I mean, actual comparison, how the two compare, at for example 200mm 2.8, or so.

Thanks in advance.

The three obvious reasons you post all depends on which camera your comparing.

Better background seperation, doesent that has to do with the glas and focalrange/f-stops?
Doubt it has to do with a larger sensor.. but someone please school me if i'm wrong.

NemethR wrote in post #15729325
Hi guys.

I would like to ask you guys about the advantages of FF against a Crop body.

What is obvious for me:
- Larger pictures
- Better Image quality.
- Less ISO noise

But there is one thing I cannot really get...

"Better background seperation"

Does anyone have a good example on this?!
FF vs. Crop.

I mean, actual comparison, how the two compare, at for example 200mm 2.8, or so.

Thanks in advance.

Shooting inside! big bonus

NemethR wrote in post #15729325
Hi guys.

I would like to ask you guys about the advantages of FF against a Crop body.

What is obvious for me:
- Larger pictures
- Better Image quality.
- Less ISO noise

This is pretty much true, although the FF advantage is going to mainly be noticeable here in very large prints. It also assumes we are comparing cameras from the same generations like a 7D/5D2 or a 30D/5D classic.

A bigger difference to me is how the lenses match up. I use a 70-200 on FF as an indoor sports and portraits lens. It's too long for that on 1.6X, but I see people using 70-200's for field sports on 7D's, where it would feel way too short on a 5D3. Same lens feels different due to the field of view range.

Another key difference for FF is on the wide end. There isn't really anything like the 24/1.4 or 17 TS-E available with the same FOV on 1.6X.

I have no back to back shots, but the way this works is that when you have a FF body you will tend to shoot everything with focal lengths about 60% longer to achieve the same framing you would have on 1.6X (so long as you are not running out to the longest focal length you own).

So when you do this, the FF camera will give a little shallower DOF due to using the longer focal length. The best comparison would be using a 50L @ f/1.2 on a 7D vs an 85L at f/1.2 on a 5D3. The FOV will be the same, but the 5D3 will deliver a bit less DOF owing to the longer focal length.

IMO this is less of an issue at the long focal lengths (where blurring a background is easy anyway). But it is different at the wide end.

This shot is on a FF camera with a 24mm lens at f/1.4. You would need a 15mm f/1.0 lens on 1.6X to create the same look, which does not exist.

Are you aware of DOF Master?
Online or downloadable app to calculate depth of field.
You can enter camera (sensor size) / focal length and aperture and get DOF result.
Or just refer to a table.

For your question - at 200mm F2.8, is the subject same distance away or are you going to move subject so it is framed the same in both photos - crop sensor and FF?
Or would you change lenses and leave subject the same distance from camera?
That's why I think DOFMaster is your answer - you decide variables

Choderboy wrote in post #15729411
Are you aware of DOF Master?
Online or downloadable app to calculate depth of field.
You can enter camera (sensor size) / focal length and aperture and get DOF result.
Or just refer to a table.

For your question - at 200mm F2.8, is the subject same distance away or are you going to move subject so it is framed the same in both photos - crop sensor and FF?
Or would you change lenses and leave subject the same distance from camera?
That's why I think DOFMaster is your answer - you decide variables

I actually think DOF calculators confuse people because they plug in the same variables (one focal length, one aperture and one focus distance) and then come away thinking the 1.6X format will actually have just a hair less DOF. This is an incorrect impression though because the situation entered is not making for the same photograph.

The FF body would have a much larger field of view. Adjusting the focal length to get the same field of view is the more realistic scenario, at least up to the point where one becomes limited in what focal lengths they have.

And at this point, one is cropping, so format comparisons become irrelevant in the focal length limited case as we will crop to the same final dimensions.

DOF is the same for both formats, the difference is in the field of view.

If you shoot a subject with both formats using a 200mm lens at F2.8 and fifteen feet away, the DOF is the same. The difference is you would be seeing less if the subject with the "crop" format due to the increased magnification. So, to get the same framing as the the "full frame" camera, you would have to move back with the crop camera, which would put the subject at a greater distance away, and also changing the relationship of the subject to the background, resulting in more of the background being in focus.

This is true regardless of focal length...the crop camera will always have to be farther away from the subject to keep framing the same as compared to a full frame camera (with the same focal length lens). Of course, you can change focal lengths to a lens with a similar field of view (a wider lens), but that lens will have different DOF characteristics. It's all about the relationship of the subjects distance from the camera, the background, and the F-stop used. Of course, in theory, with the right focal length and F-stop you can create a similar shot to a full frame camera at the same subject distance, the problem is that in reality, there may not actually be a lens option to do so (more of a problem with on the wider end of things).

Thanks for the answers!

So, I am thinking on buying a 70-200 f2.8 lens (Non-IS, IS, IS II depends on the money i will have for it)
The main thing is, how would portrait shots shoot with the 70-200 compare on the 7D vs 5D2 (or 3)...

I am really thinking of buying my first FF camera, but I am confused, and not really convinced it that is really such a big advantage over Crop.

Shooting wide angle without the need for crazy super ultra mega wide angle lens.

filmjuicer wrote in post #15729495
DOF is the same for both formats, the difference is in the field of view.

If you shoot a subject with both formats using a 200mm lens at F2.8 and fifteen feet away, the DOF is the same. The difference is you would be seeing less if the subject with the "crop" format due to the increased magnification. So, to get the same framing as the the "full frame" camera, you would have to move back with the crop camera, which would put the subject at a greater distance away, and also changing the relationship of the subject to the background, resulting in more of the background being in focus.

This is true regardless of focal length...the crop camera will always have to be farther away from the subject to keep framing the same as compared to a full frame camera (with the same focal length lens). Of course, you can change focal lengths to a lens with a similar field of view (a wider lens), but that lens will have different DOF characteristics. It's all about the relationship of the subjects distance from the camera, the background, and the F-stop used. Of course, in theory, with the right focal length and F-stop you can create a similar shot to a full frame camera at the same subject distance, the problem is that in reality, there may not actually be a lens option to do so (more of a problem with on the wider end of things).

If you want to take the same picture with cameras having two different format sensors, the only way you can do it is by changing focal length. If you move the camera, you change the perspective and therefore the picture (unless the subject is flat and parallel to the sensor ). With the different FL comes a different DoF for a given f stop and focus distance.

filmjuicer wrote in post #15729495
If you shoot a subject with both formats using a 200mm lens at F2.8 and fifteen feet away, the DOF is the same. The difference is you would be seeing less if the subject with the "crop" format due to the increased magnification. So, to get the same framing as the the "full frame" camera, you would have to move back with the crop camera, which would put the subject at a greater distance away, and also changing the relationship of the subject to the background, resulting in more of the background being in focus.

Okay, NOW I begin to understand, this explanation has helped me a lot.

So if I read it well, since with a FF camera I need to go CLOSER to the subject to have a proper framing, the background would be more out of focus, since the distance between camera and subject changes, meaning the camera would have a shorter focusing distance, thus blurring the background more...

NemethR wrote in post #15729528
Okay, NOW I begin to understand, this explanation has helped me a lot.

So if I read it well, since with a FF camera I need to go CLOSER to the subject to have a proper framing, the background would be more out of focus, since the distance between camera and subject changes, meaning the camera would have a shorter focusing distance, thus blurring the background more...

Yes.

JeffreyG wrote in post #15729400
This shot is on a FF camera with a 24mm lens at f/1.4. You would need a 15mm f/1.0 lens on 1.6X to create the same look, which does not exist.

Great shot, really nice how the subject is seperated from the background.
I wonder how the picture would look like at f2.8 (but that is not relevant here).

Your explanation with the "15mm 1.0" really helped me get an idea, how it works on the wide end of the focal range.

NemethR wrote in post #15729528
Okay, NOW I begin to understand, this explanation has helped me a lot.

So if I read it well, since with a FF camera I need to go CLOSER to the subject to have a proper framing, the background would be more out of focus, since the distance between camera and subject changes, meaning the camera would have a shorter focusing distance, thus blurring the background more...

That's about right, although you would be much better to think of the change you need to make in changing the focal length.

If you move closer with that 200mm lens and the FF camera (to only 10 feet) the framing at the subject will be the same, but the perspective will be different.

Really, the correct comparison (for the same photo) is that you use a focal length 60% longer on the FF camera.

So if you took a shot at 200mm, f/2.8 and 15 feet on a 1.6X body and you want to take the same shot on FF you need to shoot 320mm, f/4.5 and 15 feet with the FF body. That gives the same perspective, same field of view and same DOF.

The effect of moving the camera closer to the subject has that effect on the background. However, my comment was based on the caveat that "same framing is not the same as same picture".