Happy but strange M6 TTL result.

<p>A few weeks ago I was out shooting in bright sunshine with my Leica M6 TTL and Zeiss 35mm f/2 Biogon lens. I became suspicious of the meter readings I was getting as they were frequently above the "Sunny 16" rule, something that just about never happens in the UK :-)</p>

<p>When I got home I checked the meter against the meter in my Canon 5D MkII and also the light meter app on my iPhone. I found that the Leica meter was overexposing by 1.5 to 2 stops. I tried it with different lenses too.</p>

<p>I sent the M6 to Leica specialist Malcolm Taylor in England. In less than 24 hours he had tested the camera fully and phoned me to say that his test showed nothing unusual and that the meter seemed to be within half of stop of a few other cameras including another M6 TTL. He insisted on keeping hold of the camera for another week so he could test it out in the field. At the end of it all he assured me that the camera and meter were working perfectly. He only charged me £30 ($45) for the work including the return postage. Amazing service!</p>

<p>Anyway, I am just wondering if any M6 TTL owners have found metering discrepancies between it and the meters of other cameras.</p>

<p>I've just tried it using a white monitor screen for light source. Setting 400 ISO and 1/125, my Canon 70D indicated an f-value of 7.1 and my M6 Classic indicated an f-value of halfway between 5.6 and 8, i.e. 6.7. I also tried an outdoor shot and again there was about a half stop over exposure in the Leica.</p>

This may ot may not be of relevance but I noticed when I dropped a Leica flash onto either of my two M6TTLs, the body

reported the wrong ISO to the flash (1/3 ot 1/2 stop off). I sent it to Leica and they said nothing was wrong -- maybe I

described the problem poorly.

 

Anyway, if there is some internal inconsistency in the internal logic where ISO is interpreted differently than what the dial

is set at, that would account for an inaccurancy in metering. I wouldn't bring this up if BOTH my M6TTLs didn't have the

same odd behavior.

 

The flash I used was an SF24D.

 

I'd be curious what others can report if they have an M6TTL and a Leica flash which reports the ISO set on the body of

the camera.

<p>Was your film over-exposed, Jamie?</p>

<blockquote>

<p>Canon 5D MkII and also the light meter app on my iPhone.</p>

</blockquote>

<p>They are likely to have different metering patterns from the M6TTL. Also they are calibrated for digital exposures (to preserve highlights) and the M6TTL may be more calibrated for negatives (to preserve shadows.)</p>

<p>Thanks Guys,</p>

<p>Like Harry, I also tried my M6 against a white monitor screen. I also compared it to my Canon AE-1 Program and, again, the Canon was 1.5-2 stops different. Very strange indeed.</p>

<p>Mukul, I was so convinced that the meter was faulty that I tried to compensate for it during development and made a bit of a mess of it so the resulting negatives can't be relied upon.</p>

<p>Fred, that's a good point but my AE-1 matched up with the DSLR and light meter. Sorry, in my initial post I should have said that the M6 appeared to be <strong>underexposing</strong>. If a film camera is going to err on the side of caution I would assume it would overexpose. Even so, slide film requires dead on metering so I doubt an overexposure safety net would be part of the manufacturer's design.</p>

<p>I suppose the real test would be to run a roll of slide film through the M6.</p>

<p>From what I've heard, the meter on the M6 is non-adjustable. Malcolm checked absolutely every possibility including the batteries, the battery contacts, the condition of the white spot on the shutter curtain, different lenses, ISO dial etc and could find no fault.</p>

<p>I had a few rolls of Portra 160 that I shot months ago with the M6 that I have been neglecting. I developed them tonight and, from initial inspection, the negs seem to have come out perfect.</p>

<p>My next plan is to engage "fire and forget" mode. In other words, I am going to continue using the camera as normal and develop as normal and see what happens. My purpose for this post was to see if other people have noticed metering discrepancies between their M6 and other cameras.</p>

<p>Thanks again.</p>

<p>Wow, I have just tested it again and now it gets even more weird...</p>

<p>When the M6 is set to ISO 100 or ISO 80 the meter readings match my other cameras and iPhone light meter perfectly. However, if I increase the ISO to 125 or higher (or ISO 50 or lower) then the readings are almost two stops out. Looks like I'm going to have to contact Malcolm again. This can't be right. I am thinking it could be a faulty ISO dial.</p>

Are you sure you're not doing something wrong? I think the TTL has a modified spot meter or center

weighted meter, doesn't it? Could be a significant difference in the reading depending on where exactly

you're pointing it.

 

If you have a hand held incident meter you might want to check against that as well.

I'm pointing the camera at a white monitor

screen so the metering pattern will be

irrelevant. I will do a more thorough test today

but, even without comparing it to other

cameras and meters, the M6 shows a 2 stop

difference just by moving the ISO dial from

100 to 125. :-(

<p>One thought that occurs to me is that the meter may be giving readings for ASA 100 regardless of the film speed set. The other, related, thought is that perhaps a simple cleaning of the ISO dial will set things right.</p>

<p>Mukul, I don't think the meter is stuck at ISO 100. It is underexposing at ISOs higher than 100. If it were stuck at 100 it would be overexposing.</p>

<p>I agree that the ISO dial sounds like the likely culprit. I'm not sure if I can clean it myself but I will investigate. Thanks.</p>

<p>After extensive testing this morning it is obvious there is a serious problem. I have been in touch with Malcolm and he also agrees that a faulty ISO dial seems likely. The camera is going in for repair again on Wednesday. Thank you all for your help and advice :-)</p><div></div>

<p>Just for fun, I just tried this with an M6 TTL and the ƒ2.8 35mm ZM vs Minolta Flashmeter F and Sekonic L-718 with spot attachment. These 3 maintained consistent readings (within 1/3 stop). Your episode had me paranoid enough to check out my gear! Best wishes in getting it sorted. Would you post back on the outcome, please?</p>

<p>"I found that the Leica meter was overexposing by 1.5 to 2 stops" first. Later, "It is underexposing at ISOs higher than 100."</p>

<blockquote>

<p>"I found that the Leica meter was overexposing by 1.5 to 2 stops" first. Later, "It is underexposing at ISOs higher than 100."</p>

 

</blockquote>

<p>I know. I initially meant to say "underexposing". If you read back through the thread I did correct myself. Sorry for the confusion. </p>

<p>Craig, that's great to hear. I will indeed post back the outcome. The ISO dial does actually look easy enough to get at... just a case of removing the film pressure plate I think. If it was a cheap camera I would have been right in there but not with my pride and joy. I shall leave it to an expert.</p>

<p>UPDATE: Malcolm has tested the camera again and ruled out a faulty ISO dial. He even substituted the entire back door of the camera to be sure. Unfortunately this means the camera needs to go to Germany as it looks to be a faulty meter that is the problem. </p>