Algernon wrote:
I had a 28mm f/2.8 M with a damaged focusing ring.
I Dremelled off the aperture lever to see how it worked
in Av with a K-5.

Seems OK.... possibly better than it did as a Manual
using the green button. f/4 gives the correct reading.


The shots were of a gray card. The RGB values were read
straight from the jpegs in an editor.

I would normally do an RGB balance before this type of test
so that they are all the same for RGB.

28mm f/2.8 M after Dremelling off the aperture lever
====================================================
200 ISO : Outside
Av Mode K-5

f/2.8 102 105 124 1/640
f/4 115 118 137 1/320 Nearest to 117/118 = Correct Exposure
f/5.6 131 134 151 1/160
f/8 131 134 151 1/80
f/11 145 148 165 1/30

JAK wrote:
I think you're using different mores to each other!

Steve is in Av, Algi is in M.

John

prsjnb wrote:
That would be my understanding too, Chris. In practice, however, I have found repeatedly that I can shoot in A-mode over a range of 3 stops (1.8 - 5.6 on my K 55mm, for example) and still obtain well exposed shots (even when shooting JPEGs): a practice I wouldn't dream of indulging in with either the K20D or the Samsung GX-10, which I presume behaves similarly to the K10.

Is it possible that this different, and completely counter-intuitive, behavior of the K5 when compared with the earlier bodies could be function of its sensor: in particular its enhanced dynamic range and hence greater exposure latitude?

Just to be clear, it was not my intention to suggest that one could dispense totally with stop-down metering when using the K5 with manual lenses. Rather, I was seeking to communicate that this 'fortuitous aberration' makes the use of manual lenses with the K5 a little less demanding and somewhat quicker.

Best wishes,

Jon