Dof Marking on the m8

[raytoei@gmail.com]

hi. pls point me to the right direction as i am a film shooter who recently inherited a m8.

does the dof markings on my 35/f2 still apply to the m8 ?

eg. in film, focusing at 5m, f8 on the 35f2 gives me a dof coverage from 2.5m to infinity. does this still apply to the m8 ?

raytoei

 

[Broke]

Think the general rule is to be a stop more conservative on digital...
Cheers,
Jim

 

[Bill Clark]

Does the M8 have a full frame sensor?

 

[jsrockit]

Well a crop sensor should have more depth of field (effectively) at each f/stop, but i always found zone focusing on it to be harder than film. Broke might be closer to right here.

 

[Bill Clark]

Here is info. I found from the Leica forum:

http://www.l-camera-forum.com/topic/97090-request-m9-m8-bokehdof-comparison/

Hope it helps.

Another interesting spot:

http://www.cambridgeincolour.com/tutorials/depth-of-field.htm


All this stuff creates a circle of confusion in my mind!

 

[raytoei@gmail.com]

thanks all. i sort of understand now: with a m8, the dof markings on the 35f2 doesnot really apply and the dof is shallower.

 

[KismetSky]

The DoF markings will still be correct.

The linked thread above and the arguments for/against the crop sensor is that for a given field of view (FoV) of a subject, the crop sensor will have more DoF (that is because you will be farther away from your subject).

For instance, if you take a head/shoulder portrait with a 35mm on FF, you will stand about 1 meter away. To accomplish the same with the same 35mm on the M8, you will stand 1.5 meters away, increasing DoF.

To use your example from above:

eg. in film, focusing at 5m, f8 on the 35f2 gives me a dof coverage from 2.5m to infinity. does this still apply to the m8 ?

If you take one photo with a film M and then with the M8 without moving, you will still have the exact same DoF, but the frame will cover less of the scene.

 

[Fraser]

As already said its just like cropping full frame so depth of field is the same except I did read somewhere for some complicated reason depth of field does change slightly, can't remember why but it's so small makes no difference at all.

 

[BLKRCAT]

I could see DOF changing because of the circle of confusion in the lens. But this would be so minute. DOF markings would still be accurate.

KimetSky explains it perfectly. With a FF camera you can spend more time at the closer end of focus of a lens giving shallower DOF, meanwhile with a crop sensor you'll spend more time focussing further where the lens has a greater DOF.

Crop sensor literally means crop in your images. Imagine a 35mm of "FF" shot with 30% of the top bottom and sides cut off.

 

[jaapv]

DOF does not exist really. There is just one area sharp in any image: the plane of focus. DOF is the area of acceptable unsharpness. For me that is zero.

 

[Dwig]

DOF does not exist really. There is just one area sharp in any image: the plane of focus. DOF is the area of acceptable unsharpness. For me that is zero.

It exists, but it is not a case of everything in a particular range is sharp. It's that what is in that range is acceptable, though not perfectly sharp.

Everyone's standards are different. Most 35mm film DOF tables are based on optical printing at around 8x10-11x14". Since most digital users expect/demand sharper images and print larger more often, the old film based DOF tables don't accurately apply to their usage.

Comparing the DOF two cameras with different images sizes but using the same FL lens is rather pointless as it doesn't correlate with real world usage. The comparison should be done with lenses of matching FOV instead.

If you use the same CoC (read: effectively the same sharpenss standard) with lenses with the same FOV, the smaller format will have the greater DOF at any one f/stop. If you mix in the different expectations from digital and film then you often find that an APS-c/h digital camera may have less DOF, in practice, than a 35mmFF film camera when images are optically printed (not scanned, sharpened and printed digitally - that's a whole new layer of confusion...).

 

[rodinal]

thanks all. i sort of understand now: with a m8, the dof markings on the 35f2 doesnot really apply and the dof is shallower.

Yes, you got it right.
You can still use the markings, but reading distances at the next wider aperture.

 

[B-9]

Ive never had a problem scale focusing lenses on my M8,

But, I use the Rangefinder for critical focus and shallow DOF.

Scale focus in my world means f8.0-16 in good sun, which allows for a generous in focus area, otherwise your M8 has a nice accurate focusing mechanism built in! No need to look down!

 

[Fraser]

thanks all. i sort of understand now: with a m8, the dof markings on the 35f2 doesnot really apply and the dof is shallower.

no thats not right dof is exactly the same and dof of field is not shallower.

 

[rodinal]

no thats not right dof is exactly the same and dof of field is not shallower.

No, you are wrong.

It's true that the physical behavior of any given lens does not change depending on what kind of camera or device you mount behind it. But the acceptable circle of confusion is a parameter proportional to the size of the sensor(film) so, for a smaller sensor (and same lens and same aperture) the D.o.F. becomes shallower.

The acceptable circle of confusion is a parameter associated with the sensor size, is not related to the lens.

D.o.F. markings on 35mm lenses are calculated assuming a circle of confusion adequate for 24x36mm film size (full frame sensor size). If you use these lenses with a smaller sensor, those marks are no longer valid, but they are still useful if you know how to interpret them.

You can either check the theory or do the test.
Better both if you can.

 

[Fraser]

No, you are wrong.

It's true that the physical behavior of any given lens does not change depending on what kind of camera or device you mount behind it. But the acceptable circle of confusion is a parameter proportional to the size of the sensor(film) so, for a smaller sensor (and same lens and same aperture) the D.o.F. becomes shallower.

The acceptable circle of confusion is a parameter associated with the sensor size, is not related to the lens.

D.o.F. markings on 35mm lenses are calculated assuming a circle of confusion adequate for 24x36mm film size (full frame sensor size). If you use these lenses with a smaller sensor, those marks are no longer valid, but they are still useful if you know how to interpret them.

You can either check the theory or do the test.
Better both if you can.

I'm sure you are right and I mentioned earlier in the thread about this, couldn't at the time remember the reason, but in real world use i dont think it matters.