From a recent (leica) magazine a very interseting artcle on depth of field and crop factors.
To summarise we all know the longer the focal length of a lens the shallower the depth of field at the same aperture..(that is why we like to use medium / lareg format for shloow depth of field in the studio.)
So with the digital camera crop factors this 'problem' is made even more severe.
An aperture of F2.8 on a full frame 35mm film becomes on a dmr / M8 F3.8. On a 4/3" camera a F5.6. On a digilux F11 etc. etc.
So with the new M8 being a 1.37 crop, and therfore needing wider lenses to get the same focal lenght we are used to, this enlarging of the minimum depth of field will become greater due to the crop factor on the depth of field and the inherent greater depth of field the shorter focal length lens.
If you love your 35mm F1.4 lens focal length you will need a 24mm F2.8 lens to equate this. So your F1.4 super shallow depth of field becomes F4 in terms of depth of field.
So my question is: With the very shallow depth of field being so important in much street, candid photography to isolate your subjects, is this somthing that will affect people when making the choice to buy the digital M rather than sticking to film?
not sure i agree about practical DOF changing with crop.
DOF is measured by the acceptable size of the circle of confusion on the film plane, so technically, if the image plane is smaller, the circles of confusion would be smaller, implying a larger DOF for a given aperture, which is the argument presented above.
However, if you compare the image with a full frame, you have to make them the same size, which enlarges the cropped image and it's coc and equalizes the DOF.
Yes I may have misunderstood part of the article and it may have been saying simply that the dof is multiplied by the crop factor only once when working out the lens you will need to get an equivalent focal length.
I.E a 35mm full frame lens would need a 24mm lens on a 1.37 crop camera to equal the 35mm focal length and by the nature of the wider lens the depth of field is larger at eqivalent apertures..so a 2.8 aperture on the 24mm lens gives the same depth of field as F4 on the 35mm lens. (on a 4/3 " camera you would need a 17mm lens to equate a 35mm full frame lens and so again by the nature of the wider focal length the F2.8 depth of field would be equal to the F5.6 on the 35mm lens).
As a prospective M8 purchaser and it being my only Leica, I presume I would want to acquire the 35mm lens to achieve the effective focal length of around 44, correct? I want to wade into the Leica pool with a single lens and I'm wavering between the effective focal lengths of 37(28) and 44(35). Thoughts on a first lens?
One thing about this 10meg Leica M that disturbs me, is that I hear a lot of talk about certain markets that will not accept anything smaller then 12 megapixels. It makes it sound like I'm going to be buying into obsolete technology before it's even released. Anyone else think about that?
Well, certain markets won't accept anything less than MF drum scanned trannies, either, but that restriction won't be a limiting factor for most image sales.
The DMR is "only" 10Mp, and some pretty good images have come out of that.
It all depends on final image size, and—dare I say it—image content. I'd be confident that the M8 will produce fine images.
I am hoping that Photokina might preview a Zeiss Ikon digital: the Ikon system and the lenses look great, already.
You must remember that the leica M digital is a digital version of a 35mm rangefinder camera..not anything more (or less) than that (i.e. medium format, shift, etc) so pretty much any market that accepted images from the film based 35mm system will accept images from the M digital based system.
As an example a company that would only accept medium or large format trannies before may not now accept anything shot on 35mm digital, be it from 1dsmkII or leica digital M or leica M7.
As another example getty images' digital submission requirements are 48mb files and they give a list of digital camera (the nikon D200 being the base camera) that they feel will produce acceptable results for them..but of course at the end of the day you still need to expose properly, etc for your images to be usable. But with images from the D200 being accepted in terms of raw image quality there is a good chance of image shot on the digital M being accepted also. ( But of course with getty, as with everyhting else, there is much more than just the camera you are using)
