# On the primacy of exposure

Started 5 months ago | Discussion thread
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 Re: DOF + Highlight detail (+ noise) = Answer In reply to Jack Hogan, 5 months ago

Jack Hogan wrote:

bobn2 wrote:

Jack Hogan wrote:

My educated guess (EDIT: is the editor taking out spaces? It screws up formatting):

EV...... F/.... Image
15.6... 11.1.. D
15 ......9.1 ...B
14 ......6.4 ...C
14 ......6.4 ...E
13.3 ...5.0... F
10.5 ...1.9 ...A

Sorry, 0 out of 6.

Buzzzzz! It's really hard to determine front to back sharpness with all the changes in tonality, microcontrast and especially sharpness (not just DOF) at different apertures. Too many variables...

What about the groupings, I could easily have swapped D and B and A and F?

EV ......F/..... Group
15ish ..9-11.... B-D
14ish ..6.4 ......C-E
10-13 .2-5...... A-F

By looking at the grass just in front of the gate, this is highest to lowest sharpness imo (with huge license for the last three, as downsizing takes away valuable detail clues):

E, A, F, C, D, B

If you reversed it, it would be 1 out of 5, and quite close on the groupings. I think you are getting good information from the sharpness, but ascribing to the wrong cause (it isn't DOF differences)

Since you focused on the gate, assuming a 50mm prime it should be sharpest around f/4-6,

You are making an unwarranted assumption there.

so one would guess 13.3, 14, 14 for E, A and F respectively. Comparing this to the list above compiled looking at far detail (which I confirm with perhaps the inversion of B and D, B being sharper) I would suggest:

EV...... F/.... Image
15.6... 11.1.. B

No

15 ......9.1 ...D

No

14 ......6.4 ...F

No

14 ......6.4 ...A

Yes

13.3 ...5.0... E

No

10.5 ...1.9 ...C

No

But I am not happy with it

Wrong assumptions leading you astray. Here's another big hint. How come the colour is different? (remember, I said I did my best to normalise it, not very well)

--
Bob

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