A reason why people stop down m4/3s too much

Started Nov 21, 2012 | Questions thread
Jouko
Senior MemberPosts: 1,192
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Re: And to get the water fall...
In reply to Anders W, Nov 26, 2012

Anders W wrote:

Jouko wrote:

I agree with your point. The diffraction is just one factor to think about - and usually not the most important. Even sharpness is quite a lot overrated nowadays...

I guess the question of whether sharpness is overrated depends on who is doing the rating and what specifically you mean by sharpness. If you mean good MTF-values across the board, then it's hardly overrated in my book.

Of course the MTF values show some values of the lens quality, and sharpness, as ability to reproduce details, contrast etc to the final shot. Easier to work with a good lens. But maybe you should have read the next sentence too. I repeat it: With landscapes (and other subject too) the wind, clouds, DOF etc vs. shutter speed makes a lot more quality to the result than the possible diffraction loss in the sharpness.

Take a look at some old masters like Henri Cartier-Bresson or Ansel Adams... It's not the ultimate sharpness, but the whole picture.

With landscapes (and other subject too) the wind, clouds, DOF etc vs. shutter speed makes a lot more quality to the result than the possible diffraction loss in the sharpness. For the wider DOF mFT/FT format has an advantage over FF and larger formats - and opposite: for the smaller DOF...

In what way does MFT/FT has an advantage over FF and larger formats when DoF in in short supply?

There is no good or bad Depth of Field (DOF) in itself. DOF can be too small, perfect or too large. Back to the wanted results: With mFT or FT-formats it is easier to get larger DOF than with FF or larger format cameras. For example, if you use a 14mm lens at f4 (mFT) instead of using a 28mm lens at f4 (FF)... You will need the f8 in the 28mm lens to get the same (about) DOF. About, because even the lens construction makes some differences to the look and outcome of the result - meaning even the same DOF can have a bit different look.

The F8 will mean a longer exposure time than f4, if you keep the ISO the same (ah, an other variant to this discussion...). Good or bad... Depends again form the wanted result. In landscape photography the larger DOF is often a desired result. Of course, the longer exposute time can have some effects of it's own, but to keep this simpler let's assume that no showing movement is now wanted. ( With the former waterfall images this is not true: the lines of the falling water are wanted, and captured with longish shutter speed).

And the opposite: with mFT you will need a faster aperture with the same Field of View than with a FF-format camera, if you need to separate the subject from the background by a small DOF.

So, which is better? Depends what you are going to photograph.

But now and then there are situations where a photographer needs to turn the aperture beyond the F8. Quess what? Nothing dramatic happens with the result - if the step was wanted. If the result is unwanted long exposure time, then it is a mistake.

I guess nothing dramatic happens with the result whether the step was wanted or not. But you will buy whatever additional DoF you get at the expense of worse resolution within the DoF you already have, as illustrated here for example:

http://www.secondpicture.com/blog/diffraction_with_small_apertures.html

Back to the top:  The diffraction is just one factor to think about - and usually not the most important. Even sharpness is quite a lot overrated nowadays...

Cheers!

Jouko
'The best camera in the world is the one you have with you when you need it'
http://lehtokukka.smugmug.com/
http://jouko-lehto.artistwebsites.com/

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