F22.. Or... Something

[FastFashnReloaded]

Advertisement (gone after registration)

Does the M8 deal better with small apertures than, say, many digital SLRs where if you get >F11 things start to get artifacty?

 

I have been saddened that small apertures can cause interference patterns. Sucky.

[Englander]

Sorry Dana, it is physics not camera brand. With approximately 35mm format, at smaller than f/11 you have diffraction in the lens whether you use digital or film. With digital, independent of the lens aperture,the sensors also have a limit in their ability to record the airy disk without diffraction effects which is at about f/11 with pixel sites the size of those in the M8.

Joe

[wparsonsgisnet]

Dana, I can see the degradation of the image on the viewing screen beginning after f8. According to the math, the degradation is already going on before that, but it's definitely noticable at apertures smaller than f8.

 

there a thread about this, here:

 

http://www.l-camera-forum.com/leica-forum/leica-m8-forum/23431-f8-last-stop-gas.html

[FastFashnReloaded]

Sorry Dana, it is physics not camera brand. With approximately 35mm format, at smaller than f/11 you have diffraction in the lens whether you use digital or film. With digital, independent of the lens aperture,the sensors also have a limit in their ability to record the airy disk without diffraction effects which is at about f/11 with pixel sites the size of those in the M8.

Joe

 

 

Welll... Nuts. Life does not begin at F64 then. :-(

[FastFashnReloaded]

Dana, I can see the degradation of the image on the viewing screen beginning after f8. According to the math, the degradation is already going on before that, but it's definitely noticable at apertures smaller than f8.

 

there a thread about this, here:

 

http://www.l-camera-forum.com/leica-forum/leica-m8-forum/23431-f8-last-stop-gas.html

 

Thanks thanks. I really wish I could afford "medium format" digital. I'm going to end up with a TLR yet.

[lars_bergquist]

Thanks thanks. I really wish I could afford "medium format" digital. I'm going to end up with a TLR yet.

 

Sorry, but apertures are relative to focal length. This means not only that f:22 gives the same illumination/unit of area at the focal plane, if the lens is a 300mm view camera lens or sits on an M8, but ALSO that in both cases, the same proportion of the incoming photons pass close to the diaphragm blades. So diffraction works the same, irrespective of the camera format.

 

There were three reasons why in the days of Ansel & Edward people stopped down for all they were worth. First, lenses were so-so. This means that you simply had to stop them down brutally to get them diffraction limited – if at all! –Second, in large and medium format photography, depth of field is much more critical than with smaller formats. So you got an image that was sharper over all even though definition decreased a bit in the plane of best focus. –And third, big negatives meant that large ratios of enlargement were not necessary. So the decrease was not too important.

 

Finally, I do agree that a pixel-based sensor will react differently to unsharpness than a grain-based one, but this is on a really microscopic level. Note that the well-known 'fingerprints' and 'drawing' of various Leica lenses come out the same with the M8 as on film. So is the effect really important?

 

The old man from the Age of the Wet Darkroom

[ho_co]

Advertisement (gone after registration)

Dana--

Taking Lars' comments one step further: Remember that a perfect lens is diffraction-limited at its maximum aperture--for example, think telescopes and microscopes.

 

More so than other manufacturers, Leica tends to design and build its lenses closer to theoretical limits. (E Puts has remarked of several Leica designs that they are close to diffraction-limited wide open.)

 

So precisely because Leica lenses are built to higher standards than many others, diffraction effects will set in earlier with Leica lenses than with some other brands.

 

The highest compliment you can pay a lens is to say that it doesn't get any better as you stop it down, because all the lens aberrations have been eliminated and only diffraction (a physical effect, not an aberration) is left to cause image degradation.

 

--HC

[lars_bergquist]

Howard is right. I may add that a lens which is diffraction limited wide open or nearly so, in a comparison with a mediocre lens which is limited at a medium or small aperture, will beat the mediocre lens at all apertures that are wider, and will be no worse stopped down. With nearly all Leica lenses you stop down according to the subject's requirement (necessary depth of field) and not because of the limitations of the lens.

 

The old man from the Age of Meniscus Lenses

[Jamie Roberts]

Howard is right--but take heart Dana!

 

I recently shot some work at f16 on my 75 Lux. Much to my surprise (and delight), it was plenty sharp enough for a large print.

 

IOW, those same "open diffraction limited" lenses often have more than enough sharpness to spare on the M8 for printing purposes.