M7 underexposing by just over one stop indoors with 28 ASPH Summicron

[wlaidlaw]

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I took my recently acquired M7 to a family event in the UK three weeks ago. I brought with me a 1999 Special Edition LTM Summilux 50 V. 3 and a 28mm ASPH Summicron. I took six rolls of reversal film. The outside shots were all perfect with both lenses and I am more than delighted with the performance of the Agfa Precisa CT100 reversal film I was using for the first time, the lenses and the M7. However indoors with the 28 Summicron, I would estimate that the majority of shots are underexposed by around one stop. Now I am wondering if this is a bit of a characteristic of the M7 with wider lenses. The other possible reason is that "indoors" was actually during the day in a marquee, so it could be that the wider angle lens was picking too much of its exposure from the light roof. OTOH I had always understood that all M's until the M240 with its live view, took a reflective reading off the centre of the shutter blind and the exposure was very much centre weighted, so a light roof should not have too much effect. 

 

Have others had under-exposure with wide angle lenses indoors on the M7? 

 

Wilson

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[Michael Geschlecht]

Hello Wilson,

 

Which lens hood were you using on the lens that underexposed by 1 stop?

 

No lens hood can sometimes mean light "spilling in" & effecting the meter reading. More light = less exposure recommended by the meter.

By the way, the general rule for the M6 & M7 is that the meter meters a circle in the center of the frame which is about 2/3 of the short distance of the frame that you are using. Sort of. Approximately. 

 

Best Regards,

 

Michael

[wlaidlaw]

Michael, 

 

I suspect you may have hit on it. I hate the huge clunky hood, that Leica supply and so, I am using one of the neat black circular titanium GG1 hoods that I used to use with the 28mm Biogon G on my Contax G2. This provides considerably less shade than the original but I have never really had much of a problem before on digital, as the lens is quite flare resistant.

 

The other major problem with Leica's hood is that it makes it difficult to mount and unmount the lens any other way than by grasping the hood. If you do this for any length of time, the whole front section of the lens, which is only held from unscrewing by three tiny 1.5mm grub/lock screws, will come loose. The grub screws are very poor quality steel and after they have been tightened a few times like mine have, get very chewed up. A very poor bit of design. The grub screws should have been made larger, say 2mm and been hex socket screws not cheese head, with raised bosses on the ring on the rear section of the lens, to give more material for the screws to bite on. 

 

I was using the lens wide open as well, which probably exacerbated the situation with the small hood. 

 

Wilson

[Sergius]

I think the room's walls were white. So this has fooled the exposure. It's happens easier with wide lens.

[plaidshirts]

Unless you're using a proper incident meter, built in reflected light meters provide a broad guideline at best.

If there's ever any doubt, just overexpose by 1-2 stops. (Lazy, I know, but sometimes you just want a usable picture)

Because of the inherent latitude in film, slight overexpoure will not harm IQ at all, unlike digital sensors where it would mean blown out highlights.

 

I found this article very interesting: https://petapixel.com/2015/08/10/how-much-can-you-overexpose-negative-film-have-a-look/

[wlaidlaw]

Unless you're using a proper incident meter, built in reflected light meters provide a broad guideline at best.

If there's ever any doubt, just overexpose by 1-2 stops. (Lazy, I know, but sometimes you just want a usable picture)

Because of the inherent latitude in film, slight overexpoure will not harm IQ at all, unlike digital sensors where it would mean blown out highlights.

 

I found this article very interesting: https://petapixel.com/2015/08/10/how-much-can-you-overexpose-negative-film-have-a-look/

 

As I was taking pictures of opera singers, using an incident light meter might have caused a bit of disturbance 

 

Also I was using Agfa Precisa CT100 reversal film, where the exposure latitude is about half of what colour negative is and even smaller proportion of black and white. 

 

Wilson

[plaidshirts]

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As I was taking pictures of opera singers, using an incident light meter might have caused a bit of disturbance 

 

Also I was using Agfa Precisa CT100 reversal film, where the exposure latitude is about half of what colour negative is and even smaller proportion of black and white. 

 

Wilson

 

 

That would have made an interesting photo!

[edwardkaraa]

I wouldn't use reversal film with unpredictable/unfamiliar lighting. Color negative film is much more forgiving, has less contrast, and can be color corrected more efficiently. I bet you wouldn't even have noticed the one stop underexposure.

 

As for the original question, I find all M bodies systematically underexpose with wide angles, overexpose with telephotos, and just about right with 50mm lenses.

[earleygallery]

As I was taking pictures of opera singers, using an incident light meter might have caused a bit of disturbance 

 

Also I was using Agfa Precisa CT100 reversal film, where the exposure latitude is about half of what colour negative is and even smaller proportion of black and white. 

 

Wilson

 

I would have taken an incident light reading from where I was sitting/standing as the light inside a marquee is going to be pretty much the same all over (assuming to special lighting/stand).

 

I imagine the meter was 'fooled' by the bright background of the tent.

[wlaidlaw]

I would have taken an incident light reading from where I was sitting/standing as the light inside a marquee is going to be pretty much the same all over (assuming to special lighting/stand).

 

I imagine the meter was 'fooled' by the bright background of the tent.

 

James, 

 

There was also stage lighting going off and on, which did not help a lot. I think the small hood plus the light coming through the roof were the problems. 

 

Wilson

[wlaidlaw]

I wouldn't use reversal film with unpredictable/unfamiliar lighting. Color negative film is much more forgiving, has less contrast, and can be color corrected more efficiently. I bet you wouldn't even have noticed the one stop underexposure.

 

As for the original question, I find all M bodies systematically underexpose with wide angles, overexpose with telephotos, and just about right with 50mm lenses.

Edward, 

 

I know what you mean, as negative colour will happily cope with up to 3EV of over-exposure. OTOH I hate scanning colour negative film. I seem to have to spend hours fiddling around with reversal curves, tints and so on before I get something I am happy with. This will be even more the case, when in a few weeks after I get back to the UK, I switch over to using my SL camera and a Leitz BEOON reprographic device, rather than my mediocre Plustek Opticfilm 7400 scanner, which sadly is never as sharp as it should be. This is due I think, to poor film register from the cheap and flimsy moulded film carrier. Scanning reversal film is SOOOO easy in comparison. The colours are correct pretty much right off with little to no fiddling about PP. The Agfa Precisa CT100 I have been using, seems to scan extremely well, as far as colour is concerned, better than Fuji Provia, which supposedly the Precisa emulsion is based on. The substrate does look different to Provia, with a pale brown tint. 

 

Wilson

[Mark II]

I have had terrible trouble with exposure metering and the 28mm summicron - and it is largely my fault for getting used to treating the M7 metering as a quasi-spot system (I mainly use a 50mm lens).

 

The metering pattern covers roughly the central 1/3 of the frame, and in that area any bright lights or walls or whatever will pull down the exposure. For some reason, with 28mm I find it all too easy to get situations where very slight changes in the framing cause huge changes in the suggested exposure. If possible, I would use an external meter when using film without a lot of latitude...

[wlaidlaw]

I have had terrible trouble with exposure metering and the 28mm summicron - and it is largely my fault for getting used to treating the M7 metering as a quasi-spot system (I mainly use a 50mm lens).

 

The metering pattern covers roughly the central 1/3 of the frame, and in that area any bright lights or walls or whatever will pull down the exposure. For some reason, with 28mm I find it all too easy to get situations where very slight changes in the framing cause huge changes in the suggested exposure. If possible, I would use an external meter when using film without a lot of latitude...

 

My Polaris spot meter would be best but it is nearly as big as my M7. 

 

Wilson