M9 shutter speed off by 1/3rd

[jaapv]

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There was a mistype in Jaapv's original note. I don't think he meant to say that 640 on the M8 and M9 was equivalent to 400 on bog-standard Canon DSLR's, but that it was equivalent to 800, while 320 was equivalent to 400.

 

I think you have to learn how each camera interprets the appropriate exposure. After all most DSLRs have rather tricky matrix metering algorithms that try to place the whole histogram of light values reasonably, measuring the light at multiple places across the frame. The M8 and M9 take a center-weighted average reading, and add or subtract some thing to " protect the highlights." My sense has been that the M9 needs a little less highlight protection than does the M8, so I set the M8s to -0.3 exposure correction and my M9 to +0. But as a test, I just pointed both at the same light source with lenses at f/4, shutter on A and ISO 160, and got an exposure time of 1/3 second with each camera. So the exposure to set middle grey where it should be is apparently the same in each. (Sean Reid also thinks they need slightly different exposures, using real tungsten-lit scenes.)

 

scott

You're right, Scott. 640 equals 800. Mea Culpa.

[Jerry_R]

with the use of the light meter, I now notice the exposure off, from the light meter reading by about 1/3rd [...] I checked my meter against my D700, and the D700 is spot on

You shoot digital camera, you should know that light meter has nothing to do with camera ISO...

You do not need to send your camera for any calibration. That was discussed many times on DP Review, DXO Mark and other portals. DP Review even wrote special article about that...

 

Biggest outcome is, that comparing NOISE on the same ISO set on different cameras has no sense, as different producers use different sensitivity for the same ISO. Even more. At basic ones they may agree, on higher ones they can differ. So calibrating light meter is not always solution.

 

Some cameras - can even have set ISO 100, when camera uses ISO 200 and apply special tone curve - all is invisible to you, unless you open RAW in DC RAW with AUTO set to off (eg. Olympus).

 

Pls open below link:

Compare cameras

and click on ISO sensitivity section. Then point your mouse over dots. You will see what MANUFACTURERS mean by their definition of ISO, against what your light meter will most probably show.

 

Additional reading:

Sense and Sensitivity: dpreview.com Editorial blog: Digital Photography Review

Behind the scenes: Extended Highlights!: dpreview.com Editorial blog: Digital Photography Review

 

PS:

Look here, how DP Review, finally after many comments from readers! started to inform about such discrepancy on their regular tests. Let me take one of recent:

Ricoh GRX/A12 Review: 15. Photographic tests (Noise): Digital Photography Review

Have a look how Canon and Panasonic mentioned models allign theoretical ISO...

[ho_co]

Jaap, Scott--

I was under the impression that in the M9, Leica readjusted the ISO to eliminate the 1/3 stop difference that the M8 had?

 

I'm also under the impression that Canon adjusted their ISOs upward on current models to eliminate the same difference found there?

 

IOW, I thought that what was called "ISO 160" on the M8 family is now called "ISO 200" on the M9.

 

I can't cite a source, but must have deduced that from some tech sheet on the M9.

 

And somewhere I read that Canon had raised their ISO ratings sometime after Sean pointed out that the M8 and the 5D(whichever at the time) both gave 1/3 stop less exposure for a given ISO rating than his comparison meter. (Clarification: Sean made that remark in his M8 reviews. Later I heard that Canon had adjusted their ISO settings, but no reference was made to Sean's or anyone else's comments.)

 

Am I off base? Got any idea where I might have got that idea?

 

Thanks.

[Jerry_R]

Directly about M8: Leica M8 Review: 13. Photographic tests: Digital Photography Review

[andyb]

You're right, Scott. 640 equals 800. Mea Culpa.

 

Now I understand completely and logic returns . I simply didn't see it was a mistype. My apologies to jaapv for my "teachings" to a professional...

 

Andreas

[jaapv]

Jaap, Scott--

I was under the impression that in the M9, Leica readjusted the ISO to eliminate the 1/3 stop difference that the M8 had?

 

I'm also under the impression that Canon adjusted their ISOs upward on current models to eliminate the same difference found there?

 

IOW, I thought that what was called "ISO 160" on the M8 family is now called "ISO 200" on the M9.

 

I can't cite a source, but must have deduced that from some tech sheet on the M9.

 

And somewhere I read that Canon had raised their ISO ratings sometime after Sean pointed out that the M8 and the 5D(whichever at the time) both gave 1/3 stop less exposure for a given ISO rating than his comparison meter. (Clarification: Sean made that remark in his M8 reviews. Later I heard that Canon had adjusted their ISO settings, but no reference was made to Sean's or anyone else's comments.)

 

Am I off base? Got any idea where I might have got that idea?

 

Thanks.

I may be I missed that, Howard. But yesterday on an evenly lit wall, my M9 matched my Sekonic pretty well using the M8 settings.

[jplomley]

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I used a Sekonic 558 in incident mode with an M8 and M9 for 20 days in Cuba and exposures were spot on. Absolutely perfect histograms. I've always preferred an external handheld incident meter to any other modality of metering. Its simply a flawless mechanism for measuring light without bias.

[ho_co]

Thanks.

 

I'm convinced.

[wlaidlaw]

I have just done some tests with a different meter, a Polaris Duo 5º Spot/Incident Meter on a pale grey wall in north light. I used a 50mm lens at f4 and both M8 and M9 set at 160 ISO. Both the M's gave a speed of 1/45 second and the Polaris both on spot and incident gave 1/50 minus about 25% of a stop i.e. very close to 1/45 second. In practical use I find the M9 is less prone to over-exposure/blow out with wide lenses than the M8. Maybe this is due to the grey metering strips and maybe to the extra head-room with 16 bit DNG's.

 

Wilson

[@bumac]

 

Ansel, Ansel, where are you when we need you?

[rebelfocus]

A very interesting thread...

 

I also find the M9 exposure different from the M8 but have my findings are slightly different from others.

 

With the M8 it was easy to clip highlights and like others I tended to dial in - 1/2 stop on very sunny days to shift the histogram slightly to the left.

 

With the M9 it seems to be set to underexpose by 1/3 to 1/2 stop by default. I say this because I use a Sekonic 308s to take incident readings and when I set ISO 160 on the meter and camera and shoot a Kodak grey card I always get an underexposed shot with the M9. Howvever, I set the meter to ISO 100 and camera at ISO 160 I then get perfect histograms.

 

Anyone else seeing this?