Rethinking 4/3 Depth Of Field

Started Apr 11, 2013 | Discussions thread
Great Bustard
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Re: Lovely pix and excellent presentation of your argument
In reply to Anders W, Apr 13, 2013

Anders W wrote:

Great Bustard wrote:

Anders W wrote:

Great Bustard wrote:

Anders W wrote:

Great Bustard wrote:

There are quite a few fast primes for FF that aren't particularly expensive:  35 / 2, 50 / 1.8, 50 / 1.4, 85 / 1.8, 100 / 2.

On the other hand, many of those that aren't particularly expensive aren't very good wide open and thereabout. I am not saying that exceptions do not exist, but they are hardly frequent. Most of the fast Oly & Pany MFT primes, by contrast, do very well already from the get-go, and at least some of them are quite affordable too (20/1.7, 45/1.8).

Well, I guess it depends on what you mean by "aren't very good wide open" -- I found the 50 / 1.4:

http://www.dpreview.com/forums/post/34489299

85 / 1.8:

http://www.dpreview.com/forums/post/34631434

and 100 / 2:

http://www.josephjamesphotography.com/lenses/100f2/

more than "good enough", although that's not to say that I would not be against paying more for better still.  Indeed, I paid a lot more for the 50 / 1.2L:

http://www.josephjamesphotography.com/lenses/50L/

but I have to wonder how many, if anyone, appreciates the difference.

My definition of "not very good" is something like "significantly worse than peak performance".

Hmm.  My definition of "not very good" would be more like "doesn't deliver desired results".

I am not sure the two definitions are very different.

I'm thinking they're rather different, actually.  For example, consider two lenses:  a 50 / 1.4 and a 50 / 2.8.  Both lenses peak at f/4 and have the same resolution stop-for-stop, but the 50 / 1.4 is significantly softer wide open than the 50 / 2.8.  It seems to me that your definition of of "not very good" would make the 50 / 2.8 a superior lens to the 50 / 1.4, whereas I would consider the 50 / 1.4 the superior lens, since it could do everything the 50 / 2.8 could do, and more.

Most MFT lenses are just marginally worse wide open than at peak, which they typically reach at f/4 in the center and at f/4 or f/5.6 at the edges. Since I want to use the really wide apertures far more often with MFT, due to the DoF "bonus", this is a blessing (and one of the things that convinced me to take the plunge).

I think in terms of the resolution of the final photo for a given DOF.  That is, if f/4 on mFT outperforms f/8 on FF, or f/2 on mFT outperforms f/4 on FF, then I would consider the mFT combo to be superior.

Outperforms and outperforms. How about roughly equivalent.

I wouldn't even say "roughly equivalent" -- it would depend on the particular lenses we are comparing.

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