getting accustom to FX..DOF - a double edge sword.

[san2001]

1) It IS about going wider in the context of this debate. As far as I understand, TS was trying to equalize FoV by using a longer lens (And hence, thinner DoF). My suggestion of going "Wider" was within this context, which means that go wider than the lens you normally would have thought of using on FX. It just so happens that it's the same lens as that used in the DX sample. You can use an even wider lens to get more DoF by this method, you'll just end up with a smaller file (Pixel dimension-wise) when you equalize FoV. Not a big problem with a camera such as the D800.

In simple terms: At the same aperture,

- 50mm on FX = Same FoV as 35mm on DX, less DoF (This is where the TS is right now, by all accounts)
- 35mm on FX cropped down to equalize FoV of 35mm on DX = Same FoV as DX, same DoF
- 20mm on FX cropped down to equalize Fov of 35mm on DX = Same FoV as DX, even more DoF

2) I don't know why you think that my example is about focal length when starting from the first post, I am talking about the relationship between FoV, DoF AND focal length. Not one of the three, but all three.

3) What I suggested was a solution for a specific problem that the TS faces. It in no way means that all portraits have to be shot with DX. It obviously is not something applicable in every shooting scenario. I thought this was obvious.


This is a solution that has worked for me over the years, not just for FX and DX, but also for medium format.

 

[daredevil123]

1) It IS about going wider in the context of this debate. As far as I understand, TS was trying to equalize FoV by using a longer lens (And hence, thinner DoF). My suggestion of going "Wider" was within this context, which means that go wider than the lens you normally would have thought of using on FX. It just so happens that it's the same lens as that used in the DX sample. You can use an even wider lens to get more DoF by this method, you'll just end up with a smaller file (Pixel dimension-wise) when you equalize FoV. Not a big problem with a camera such as the D800.

In simple terms: At the same aperture,

- 50mm on FX = Same FoV as 35mm on DX, less DoF (This is where the TS is right now, by all accounts)
- 35mm on FX cropped down to equalize FoV of 35mm on DX = Same FoV as DX, same DoF
- 20mm on FX cropped down to equalize Fov of 35mm on DX = Same FoV as DX, even more DoF

2) I don't know why you think that my example is about focal length when starting from the first post, I am talking about the relationship between FoV, DoF AND focal length. Not one of the three, but all three.

3) What I suggested was a solution for a specific problem that the TS faces. It in no way means that all portraits have to be shot with DX. It obviously is not something applicable in every shooting scenario. I thought this was obvious.


This is a solution that has worked for me over the years, not just for FX and DX, but also for medium format.

1. I was responding to DemonicAngelz... who specifically said using a wider focal length... and you came in and talked about wider which I now found out you meant something else... I guess we are not talking about the same thing... your context, your debate, is not mine. sorry.

2. It is more about subject distance actually, if you use cropping to solve the problem.

3. yes, but TS is talking about a specific problem. He is talking about in general how he is losing DoF on a FX compared to a DX.

If it worked for you, good for you, but it will not work for me. I tend to look at problems in more dimensions and find solutions from all angles rather than just one. But that is just me...

 

[san2001]

I see a pattern that you love to argue semantics till the cows come home. Good for you.
While you spend time looking at problems from all dimensions, I use my simple solution to help me pictures that satisfy me and my subjects. Have fun contemplating.

 

[daredevil123]

I see a pattern that you love to argue semantics till the cows come home. Good for you.
While you spend time looking at problems from all dimensions, I use my simple solution to help me pictures that satisfy me and my subjects. Have fun contemplating.

Have a good life. The feeling is mutual I guess.

I had no desire to do any discussion with you in the first place... in this and other threads, just that you kept replying to me, when I was not even talking to you... I guess we all know how it turns out. It is for the better we don't talk.

 

[san2001]

I don't know why you've got a chip on your shoulder, dude. I reply to posts online, not people. When I see posts that have something to do with matters that I have something to say about, I reply to them. Yours just happens to be some of them.

The only reason I sense a pattern in your posts is when I looked back at some of your posts and you keep doing this endless arguing routine. Obviously, you derive some sort of pleasure from it. Good for you. Maybe not so good for your blood pressure.

 

[daredevil123]

I don't know why you've got a chip on your shoulder, dude. I reply to posts online, not people. When I see posts that have something to do with matters that I have something to say about, I reply to them. Yours just happens to be some of them.

The only reason I sense a pattern in your posts is when I looked back at some of your posts and you keep doing this endless arguing routine. Obviously, you derive some sort of pleasure from it. Good for you. Maybe not so good for your blood pressure.

sounds like the chip is not on my shoulder...

I try not to respond to certain individuals because I think it is a waste of everyone's time if discussions get derailed on arguments and become not useful to anyone reading... It is not personal. I don't hate you or bear a grudge. Just that I know for a fact that your logic or reasoning coupled with mine will take the discussion to a level where I do not think will be worth anybody's time. I am proven right again here, as soon as I responded to your post.

btw, you should take a look at your past post history too...

and do note... I have the right to disagree with you or anyone in opinions. You have the same rights. so we each said our peace and it is done. whoever reading can make conclusions of their own... no need to wail when opinions differ. at least try to be civil about it. Differences in opinion is what makes the world go round.

which is also why I will end here and no longer respond to anything you have to say... just move on.

 

[ortega]

agree to disagree

 

[DemonicAngelz]

Sorry if I started an argument, guys...

 

[daredevil123]

Sorry if I started an argument, guys...

no need to apologize..

 

[Dav-C]

Since we are in the topic of FF and DOF, I was reading the British Journal or Photography comparing D800 and D800E July issue. Without AA filter, D800E has more apparent DOF as compared to D800. Their reviews are usually much more detailed in term of practical use rather than reading out the technical spec like most other megazines.

 

[DemonicAngelz]

Since we are in the topic of FF and DOF, I was reading the British Journal or Photography comparing D800 and D800E July issue. Without AA filter, D800E has more apparent DOF as compared to D800. Their reviews are usually much more detailed in term of practical use rather than reading out the technical spec like most other megazines.

Can any pros explain the science behind this? I cant see a reason why..

 

[daredevil123]

Can any pros explain the science behind this? I cant see a reason why..

Circles of confusion gets affected maybe?

 

[sf_kang]

Some talk about law of optics to understand DoF, and what affects it.

Depth of Field (DOF) is an ARBITRARY zone in front and behind the actual point of focus that is ACCEPTABLY sharp.
Theoretically, for any lens (regardless of focal length), there is only ONE exact point that is precisely in sharp focus. There is a zone in front and behind this exact focus point that remains acceptably 'sharp' (this is usually referred to as Depth of Field).

There are various parameters that affect DoF, i.e. either increase DoF or decrease DoF. E.g. if you do a landscape shot where you want sharp details in the foreground all the way to the mountains in the background, like sharpness from say 1.5m all the way to infinity, YOU WANT MAX DOF. However, say when you want to take a portrait but the background seems 'distracting' and you want to 'blur' the background and only keep your subject in sharp focus, you would want to decrease your DOF.

DoF is affected by:
1) Aperture setting: the smaller the aperture the greater the DoF for any focal length.
2) Wide angle lenses offer greater DoF than tele lenses for the same aperture setting.
3) For the same focal length, and same aperture, the DoF is less when subject to lens distance is near; DoF increase when subject to lens distance increases.
4) For the same focal length, and same aperture, the DoF 'APPARENTLY' decreases with increase in size of Image Circle. That's why for a lens 50mm shot at say f5.6, the DoF would be greatest when sensor size in smallest (like in compact cameras), and DoF is shallowest when sensor size is larger (like in FX or Medium Format sensors). So for the same focal length lens, same F-stop, the DoF on a DX will be greater than on a FX camera or still shallower on a MediumFormat (MF) camera.
5) For a lens of a given focal length (say 50mm), PERSPECTIVE remains unchanged regardless of which format it is used on, i.e. a 50mm lens will produce the exact same perspective when mounted on DX, FX, or MF. Only difference is the size of the Image Circle which results in different Field of View (FoV), i.e. a 50mm lens on a FX body will produce a picture that covers a wider FoV than the same lens used on a DX body (hence the cropped effect or so-called cropped sensor).
6) Finally, apparent DoF differences between the D800 and D800E. The D800 has a AA filter which is likely to change the incident angle at which the light hits the sensor. The D800E does not have the AA filter. Light that hit the sensor perpendicularly will be equally sharp on both the D800 and the D800E. But for light that is hitting the sensor at a greater incident angle would hit the sensor directly on the D800E (hence remain more in focus). Incident light hitting the D800 sensor actually hits the AA filter first, gets a little defracted, and may manifest itself to look a bit like less DoF.

Conclusion:
A good photographer recognises the opportunities and limitations of the law of optics and camera technologies to create the best photos he/she can. No need to burst your brain about the physical laws of optics. Observe, ask questions, learn, experiment and go out and shoot more pictures.

Cheers.

 

[Dav-C]

Can any pros explain the science behind this? I cant see a reason why..

I am not pro photographer or optic Phd or scientist, but let me just quote a bit more from the Journal that maybe matters to photography.

"It was clear that on the D800E the out-of-focus area is rendered without additional blurring from the AA filter of the D800, giving almost an extra stop of apparent DOF."

 

[Ansel]

Since we are in the topic of FF and DOF, I was reading the British Journal or Photography comparing D800 and D800E July issue. Without AA filter, D800E has more apparent DOF as compared to D800. Their reviews are usually much more detailed in term of practical use rather than reading out the technical spec like most other megazines.

I believe this may be due to the higher accutance of the 800E without the AA filter. We all know in the 800 the AA filter basically "blurs" the images to solve the aliasing problem inherrent in sensors using the Bayer Pattern configuration. This probably shrinks the range of apparent sharpness (aka DOF) slightly in the process too, which we all already know.

But the observation that the effect is equivalent to 1 f-stop of sharpness shocks me! :bigeyes:

 

[lunas]

Hey Guys,

Thank you for sharing your expertise with me. I learnt a lot through reading your post. And I have 'Like' them.
After reading, I feel that it about mindset change, I need to start to be more confident in what D800 can present in terms of high ISO.

One last thing, I realized that when you focus, re-compose and take the shot. The image has a higher probability of becoming OOF on FX...
I guess, no one use this method in FX anymore? Instead, we should use the AF points.

 

[Eddie77]

Can i ask somethings too ?? Whether large mp will affect the DOF ??

 

[rain5533]

Actually depth of field & out of focus blur is a different thing.

If you compare from DX using same angle and same aperture.

I will notice the FX will have much more DOF.

For example this photo I'll only needed the lens of 50mm f1.8G

If on DX taken with 35mm f1.8G of the blackground just so so only.

 

[daredevil123]

Hey Guys,

Thank you for sharing your expertise with me. I learnt a lot through reading your post. And I have 'Like' them.
After reading, I feel that it about mindset change, I need to start to be more confident in what D800 can present in terms of high ISO.

One last thing, I realized that when you focus, re-compose and take the shot. The image has a higher probability of becoming OOF on FX...
I guess, no one use this method in FX anymore? Instead, we should use the AF points.

really depends on the aperture being used. For F2.8 and a fair amount of subject distance you can still get away with it. With very large apertures, or close focusing, I would avoid focus-recompose method.

 

[daredevil123]

Actually depth of field & out of focus blur is a different thing.

If you compare from DX using same angle and same aperture.

I will notice the FX will have much more DOF.

For example this photo I'll only needed the lens of 50mm f1.8G

If on DX taken with 35mm f1.8G of the blackground just so so only.

I am again confused by what you are saying rain.

FX have more DOF?