The 1.3 factor problems

[sonwolf]

Symeon,

The Bob Atkins website has a detailed explanation of depth of field and its relation to digital cameras. His excellent DOF calculator will give all the relevant information for an M8.

http://www.bobatkins.com/photography/technical/digitaldof.html
http://www.bobatkins.com/photography/technical/depth_of_field_calc.html

 

[charjohncarter]

sonwolf, thanks even I can understand that site.

 

[Gabriel M.A.]

To believe that maximum aperture (the speed of a lens) remains unchanged when the focal distance has changed is a fallacy, an ignorance of the basic laws of optics.

Now the Leica people obviously wouldn't have liked to reveal all these truths when they launced their pricey object.

Leica has special pricing for those "ignorant of the basic laws of optics". It comes with a specially designed Sharparatamat f/64

 

[edrodgers731]

Bob Atkins.. "...to give the same view..."

Derp.

 

[dcsang]

Bob Atkins.. "...to give the same view..."

Derp.

Ya.. let's give that whole quote now shall we? I mean, may as well "give credit where credit's due" and all that...

For an equivalent field of view, the EOS 10D has at least 1.6x MORE depth of field that a 35mm film camera would have - when the focus distance is significantly less then the hyperfocal distance (but the 35mm format needs a lens with 1.6x the focal length to give the same view).

But ya.... the DOF is the same no matter what.. or different....

I remember this argument like it was a beer commercial.. "Tastes GREAT !!! / LESS FILLING !!!"

Dave

 

[edrodgers731]

Less filling!

Nobody is trying to compare apples to apples. How about this: Take a 47mm lens on the M8 and take a picture. Then take the same shot with a 69mm lens on an M7 from the same spot.

Damn.. Somehow it's still different. WHAT ARE WE GOING TO DO?



Now I'm just having some real fun!

 

[Bill Blackwell]

This issue is only complicated because we make it so.

Take a picture with a 35mm camera (any lens will do). Make a full-frame print (any size will do). Then trim the edges reducing its size by a ratio of 1:33:1. That's it.

This is precisely why they call it a "crop-factor."

 

[dcsang]

ya.. Jaap's right - the M8's DOF with the same lens vs the M7 yields a greater DOF.. he said it himself

With a format difference of 1.4, the difference in DOF is one stop. Add to that that the DOF is more steeply defined on a sensor than on film because of the thickness of film, the effect is enhanced. So on the M8, with a format smaller by 1.3, you cannot go wrong if you mentally visualize the DOF you would have with the same lens closed down one stop more than you actually do, compared to your film days.

Dave
(I told you I "loved" these threads....)

 

[edrodgers731]

This issue is only complicated because we make it so.

Take a picture with a 35mm camera (any lens will do). Make a full-frame print (any size will do). Then trim the edges reducing its size by a ratio of 1:33:1. That's it.

This is precisely why they call it a "crop-factor."

Yeah! We star-bellied Sneetches are better than you non-star-bellied Sneetches!

Bill, that's how I like to think about it, but the other argument is just as valid. It's like that old story about the blind men feeling up an elephant. To the one holding the tail, the one holding the tusk doesn't know squat about elephants!

 

[Ben Z]

Some people like to debate the science, and that's fine. But in terms of practical use when actually taking pictures, it's like this:

To get approximately the same composition from the same distance that I would get with my 50mm lens on my M6, I have to use a 35mm lens on my M8. A 35mm lens gives more DOF from the same distance as a 50mm lens, regardless of what the format is, so in this example, I have the DOF of a 35mm lens in the FOV of a 50. In practice, this is easily observed.

If subject isolation is a consideration, one can shoot at one f-stop wider, which reduces the DOF. Unless of course one is already shooting wide open, which is where the trouble comes. That is why I am a bit ticked that I sold my 35 Summilux-ASPH back a while, and can't see myself paying what they're going for these days.

 

[jaapv]

ya.. Jaap's right - the M8's DOF with the same lens vs the M7 yields a greater DOF.. he said it himself




Dave
(I told you I "loved" these threads....)

It appears you actually understood it....And picked up on a sloppy way of formulating .