The 80/1.7 GF on the GFX 100S has *more* DOF than calculators say

Started 2 months ago | Discussions thread
MOD Hamiltionian Contributing Member • Posts: 929
Re: The 80/1.7 GF on the GFX 100S has *more* DOF than calculators say

JimKasson wrote:

Hamiltionian wrote:

JimKasson wrote:

Not much more, but more, at least at f/2 and subject distances of 101 and 55 meters:

https://blog.kasson.com/the-last-word/are-dof-calculators-useful/

And the DOF is slightly asymmetrical, to boot.

Jim

"""If we focus on the front tree and look at the back tree, we should see the same amount of blur that we see if we focus on the back tree and look at the front tree.''''

True as long as f << S1, where S1 is the distance to the focal plane in the objects space, and definitely true in this case.

Right.

Spherical aberration is much more likely the source of the asymmetry. Especially since this is designed as a portrait lens and such an asymmetry is a feature.

I would agree that SA is the most likely suspect. What is interesting to me is that the asymmetry is slight, at least at these largish blur circles.

Yeah, does seem pretty slight.  I suppose you can only have some much SA and still meet the expectations for sharpness and contrast for a modern MF lens.

-- hide signature --

Stay Calm and Carry Cameras
https://thecentercolumn.com/

Post (hide subjects) Posted by
MOD JimKasson
MOD JimKasson
MOD JimKasson
MOD JimKasson
MOD JimKasson
MOD JimKasson
MOD JimKasson
MOD JimKasson
MOD JimKasson
MOD JimKasson
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow