[jsherman999]

It's math:

Online Depth of Field Calculator

FF sensor using a 55/1.2 w/subject at 2 meters renders :

Depth of field
Near limit 1.96 m
Far limit 2.05 m
Total 0.09 m

An APS-C sensor using the same lens, same distance to subject:

Depth of field
Near limit 1.97 m
Far limit 2.03 m
Total 0.06 m

For a grand total DOF difference of .03 meters.

3cm

Good luck measuring that on a 2D image. I doubt any trained eye can make that adjudication. Those who claim to see the difference are in la-la land. Pros I know who use FF do not do so for DOF effects, but for higher resolution and better low-light performance.

ROFL

They also would be completely different images, as the FOV would be radically different - of course the measurable "DOF" would be almost the same if you allow the FOV to vary, Bob Atkins points this out nicely!

You would need about a 36mm f/.085 or something silly like that to get the equivalent image on aps-c.

(C'mon, Aristophanes, you know this stuff (don't you?). Why try to spread false info?)


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[Aristophanes]

Of course I'll be able to tell the difference between those two pictures - one will be cropped to half the area of the other.

FOV. Not DOF.

Go to an equivalent FL and the difference is still in the cm's. You might notice in shots approach the near focus limits of a lens. Might.

[Aristophanes]

Of course I'll be able to tell the difference between those two pictures - one will be cropped to half the area of the other.

ROFL

They also would be completely different images, as the FOV would be radically different - of course the measurable "DOF" would be almost the same if you allow the FOV to vary, Bob Atkins points this out nicely!

You would need about a 36mm f/.085 or something silly like that to get the equivalent image on aps-c.

(C'mon, Aristophanes, you know this stuff (don't you?). Why try to spread false info?)


.

You don't NEED the f/0.85 because, quite frankly, most photos the difference is not noticeable. I've tried with prints and it is bloody hard to see.

It's a difference of perception rather than empirically proven observation.

[jeffshaddix]

FOV. Not DOF.

Go to an equivalent FL and the difference is still in the cm's. You might notice in shots approach the near focus limits of a lens. Might.

Comparing with equivalent FOV is the only way to do it, no one is going to use a 55/1.2 the same way on FF vs APS-C.

With the same DOF calculator you linked:
If you're using the 55/1.2 on FF, then the APS-C equivalent is a ~36mm/0.85 (good luck finding this).
If you're using the 55/1.2 on APS-C, then the APS-C equivalent is ~85/2 (an 85/1.4 @ f/2 is almost surely sharper and better optically than your 55/1.2 @ 1.2).

And of course the difference is in centimeters, the total DOF difference between your 55/1.2 on APS-C @ f/1.2 vs f/2 is only 4 centimeters, but I guarantee you'll see a drastic difference in image rendering.

Edit: Based on your post while I was typing, maybe you specifically wouldn't see a meaningful difference in your prints between f/1.2 and f/2, but a lot of us would. I see a major difference in rendering between f/1.4 and f/2 with my Nokton 58/1.4. Perhaps we're just persnickety.

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Last edited by jeffshaddix; 03-09-2012 at 08:36 PM.

[ElJamoquio]

FOV. Not DOF.

Go to an equivalent FL and the difference is still in the cm's. You might notice in shots approach the near focus limits of a lens. Might.

50mm f/1.4, 2 meters: 13 cm DOF
35mm f/2.4, 2 meters: 46 cm DOF

I think I can tell the difference.

[Aristophanes]

And of course the difference is in centimeters, the total DOF difference between your 55/1.2 on APS-C @ f/1.2 vs f/2 is only 4 centimeters, but I guarantee you'll see a drastic difference in image rendering.

Drastic?

Don't tell us, show us.

The f/2 will be sharper.

It will entirely depend on the subject.

[Aristophanes]

50mm f/1.4, 2 meters: 13 cm DOF
35mm f/2.4, 2 meters: 46 cm DOF

I think I can tell the difference.

Show. Don't tell. Post photos with EXIF to demonstrate. Enough talk.

FF FA 50/1.4
Depth of field
Near limit 1.94 m
Far limit 2.07 m
Total 0.13 m

APS-C Sigma 30/1.4
Depth of field
Near limit 1.88 m
Far limit 2.13 m
Total 0.25 m

You have to severely constrain the subject to visibly notice, and do so across a huge sample of photos.

I'm not arguing there is no difference, I am arguing that it is one thing on paper and another visibly manifest. There's a reason why major manufacturer lens designers are not making these super-fast lenses much anymore, like the 1.2's. It's a combination of visible difference vs. cost and the very limited # of times the cost is realized in the shot. We find it very hard to see a stop of difference 2D rendered. So is it worth it for the $3,000 camera body?

And, frankly, from an aesthetic perspective, most of these types of shots start to look the same. It's turning into the equivalent of the 1980's soft focus lens. Oooohh.....

[bossa]

The dog picture shown earlier in this thread would be impossible using APS-C without a 33mm F1.2 lens. That picture was taken at F2 so I'll use that as a starting point for my DoFo iPhone DOF calculations. The cameras are D700 & D7000.

FULLF 50mm F/2.0 @ 2000mm DOF = 192.44mm (1,908.40<->2,100.84)
APS-C 33mm F/1.3 @ 2000mm DOF = 193.65mm (1,907.85<->2,101.50)
APS-C 30mm F/1.4 @ 2000mm DOF = 252.75mm (1,881.58<->2,134.33) (sigma)
APS-C 31mm F/1.8 @ 2000mm DOF = 304.89mm (1,859.11<->2,164.00) (FA LTD)

The Sigma would get close but would be wide open and lack contrast and the 31LTD would be way off the mark.

So even a 'cheap' standard lens on a FF would outperform expensive LTD lenses on APS-C and come up sharp and contrasty and with a few F stops to spare if it were a faster lens.

[RXrenesis8]

Show. Don't tell. Post photos with EXIF to demonstrate. Enough talk.

Clicking each photo navigates to the EXIF info page.



Vina | Flickr - Photo Sharing!



Election in Luxembourg | Flickr - Photo Sharing!

I'll let you guess which one is the FF 50 1.4 and which is the APS-C 35 1.4.

[eurostar]

I don't understand this debate. There is a difference? Sure. Are there cameras that allow you to have the results you desire? Sure. Go out and you'll find cameras new or used with sensors from 12 to 38 MP with the magical dimension of 24x36mm.
It's really the same situation a Canon or Nikon shooter that want to shoot medium format has to face. Go out and buy a Pentax, a Mamiya or a Hasselblad. Or lament forever that your brand doesn't make a medium format, while others happily makes picture.

[bossa]

When you have a number of FF lenses it almost seems pointless to have to buy another lot for a bigger sensor. Many people, myself included, have, more or less, learned the ropes in the APS-C format and that comes with a degree of awakening. Beyond that you then need to decide if bigger is really more where you're art is concerned. I started shooting with a K2 and ended up with a LX and MX many years ago but I sold them for a song when I went all out into music (pardon the pun). It's only over the past 8 months, since I've been back into photography, that I have begun to understand what's going on intuitively with regard to format after being away for 28 years. So, as many others are doing, I'm trying to work out if it's worth the journey across to another brand for the FF experience.

[darrenleow]

On a side note.. I missed a D3 on fleabay the other day.. It ended up going for $2028.... Peanuts for that camera! I tried to bid at the last few sec.. And someone else must have beat me by 1/2 a second... Doh!

Don't feel too bad.. that D3 didn't sell because it was under the seller's reserve price

[eurostar]

When you have a number of FF lenses it almost seems pointless to have to buy another lot for a bigger sensor. Many people, myself included, have, more or less, learned the ropes in the APS-C format and that comes with a degree of awakening. Beyond that you then need to decide if bigger is really more where you're art is concerned. I started shooting with a K2 and ended up with a LX and MX many years ago but I sold them for a song when I went all out into music (pardon the pun). It's only over the past 8 months, since I've been back into photography, that I have begun to understand what's going on intuitively with regard to format after being away for 28 years. So, as many others are doing, I'm trying to work out if it's worth the journey across to another brand for the FF experience.

I understand this, I have been into pentax from 1981 to 2003, then switched to digital with a coolpix, then three years later I came back with istD and then K10D and started to buy only used FF lenses (I sold all the ones I had previously, minus F*300/4,5). But since then, I opened my eyes, saw that Pentax had reasons to try to enter digital medium format, she did it successfully, to me it seems evident that it's a niche where it can become a big player, while with FF it will be always a secondary player. I am not saying it should or it shouldn't enter FF, I have no idea how much viable for the company it would be. What I am saying is that if one wants to shoot FF, it should stop to loose time waiting for a FF camera, and buy one that does exist. Many years ago, when I wanted to do Large Format, I didn't started to wonder win Pentax would begin to make large format lenses and large format view cameras, I simply bought some from other manifacturers. The fact there are a lot of FF Pentax lenses out there to Ricoh-Pentax means little, I think, since they have been sold long ago. I have no hope in a FF from Pentax, I wonder why people spend so much time here trying to affirm the superiority of full frame to the unfaithful ones instead of simply buy one and be happy.

[bossa]

I understand this, I have been into pentax from 1981 to 2003, then switched to digital with a coolpix, then three years later I came back with istD and then K10D and started to buy only used FF lenses (I sold all the ones I had previously, minus F*300/4,5). But since then, I opened my eyes, saw that Pentax had reasons to try to enter digital medium format, she did it successfully, to me it seems evident that it's a niche where it can become a big player, while with FF it will be always a secondary player. I am not saying it should or it shouldn't enter FF, I have no idea how much viable for the company it would be. What I am saying is that if one wants to shoot FF, it should stop to loose time waiting for a FF camera, and buy one that does exist. Many years ago, when I wanted to do Large Format, I didn't started to wonder win Pentax would begin to make large format lenses and large format view cameras, I simply bought some from other manifacturers. The fact there are a lot of FF Pentax lenses out there to Ricoh-Pentax means little, I think, since they have been sold long ago. I have no hope in a FF from Pentax, I wonder why people spend so much time here trying to affirm the superiority of full frame to the unfaithful ones instead of simply buy one and be happy.

i have to agree. There are countless FF threads going back 5 years or more on this forum.. If it really means that much then there's only one answer.

[Jan67]

And, frankly, from an aesthetic perspective, most of these types of shots start to look the same. It's turning into the equivalent of the 1980's soft focus lens. Oooohh.....

Aristophanes, allow me one personal question.
What was the reason you bought D700 and couple of Nikon lenses?
Would you do it once again ?

EDIT: Please understand this question from the FF vers APSC point of view.