ISO ratings on M2

[Jigster]

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Hello

 

My question is pretty simplistic, sorry, but as a digital user coming to film, I'm lacking instinct I think. So I have a roll of Ektar Colour 100 to load and the closest value to 100 on the ISO dial, as you'll all know, on the M2, is 160. However, equally one could say the 160 is actually closer to ISO 200? I don't imagine there's a hell of a difference between the two, (degrees of under or over exposure I suspect) but when giving it to the lab, should I say it's been pushed a stop? 

(I know there's also ISO 60 on the dial but that feels too slow for my needs)

Finally, how about when using the Sunny 16 rule? Imagine I've loaded a roll of ISO 100 and set it to ISO 160 on the M2, would I match my shutter speed at 1/250 or 1/125? 

Appreciate this is basic and I'm all for experimenting and learning the practical way, (when we finally get some decent weather), but meantime, any advice is helpful.

 

Thanks.

[jaapv]

This is not a digital camera or one with an A setting. The dial does not connect to any exposure in the camera at all.

 

As the M2  has no metering ( the M5 was the first M camera to have it), it is utterly irrelevant what you set the dial to, it is just to help you remember what film you put in.

 

The external exposure meter and/or your skills at exposing will determine the outcome.

 

So, you judge or measure the light, you decide how you want your image exposed, then you set aperture and shutter speed and press the button. If you are starting out on film I would forget about pushing and pulling for the time being, gain some experience first.

 

The same goes for Sunny f16. It works, but in experienced hands. Buy an exposure meter.

[ktmrider2]

If you are shooting on a sunny day with Ektak 100, the closest shutter speed is 1/125 and the f/stop should be f16 according to the rule.  However, a lot of us find a half stop more light to be closer.  I usually shoot using a "sunny f11" rule myself.  Film always does better with a bit of overexposure.

 

And the relationship between ISO numbers is exactly the same as between f/stops and shutter speeds.  If you double the ISO (100 to 200), the film has double the sensitivity to light.  For example, if the correct exposure is 250th at f8 with ISO 100, it would be 250th at f11 using ISO 200.  If you halve the ISO value, then film requires exactly double (1 stop or doubling the shutter speed) more light.  This applies to either film or the ISO setting in digital.  

 

If you go from ISO 100 to ISO 1600, you must decrease the exposure 4 f stops (ISO 100 to 200, 200 to 400, 400 to 800, 800 to 1600).  Once you get the concept of double or halving the number means doubling or halving the amount of light as well as increasing or decreasing the fstop and shutter speeds, moving from one set of numbers (shutter speed, fstop, and ISO) to another becomes second nature.

 

And you may want to invest in a light meter which is a whole different subject.  I would suggest the Voightlander II which mounts on the hot shoe of the M2.

Edited March 18, 2018 by ktmrider2

[Jigster]

Thanks for the replies both.

 

Interesting and useful about the Sunny 11 approach. I have a light meter already.

 

I naturally assumed the dial was ISO settings, so that's good to know. 

 

Cheers

[Richardgb]

<snip>

Film always does better with a bit of overexposure.

<snip>

 

I think it would be better to say negative film can benefit from (slight) overexposure - in my experience perhaps 1 stop.

 

However, with transparency / slide film it is usually better to err on slight underexposure.

 

Having said this, it all depends on how you are metering the subject (ideally, you are pointing your meter at an area which matches the 18% reflectance calibration of the meter). As others have said, stick to the basics if this is your first venture into manual exposure and film.

[250swb]

 

 

I naturally assumed the dial was ISO settings, so that's good to know. 

 

 

 

The dial is a reminder for the ISO and film type, for people who have their Summer holiday at the start of the film, and their next Summer holiday at the end of the film.

[Ouroboros]

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Hello[/size]

 

 

Finally, how about when using the Sunny 16 rule? Imagine I've loaded a roll of ISO 100 and set it to ISO 160 on the M2, would I match my shutter speed at 1/250 or 1/125? [/size][/font][/color]Appreciate this is basic and I'm all for experimenting and learning the practical way, (when we finally get some decent weather), but meantime, any advice is helpful.[/size]

 

Thanks.[/size]

If you carry a smart phone, you might find one of the light meter apps more useful to begin with.

[Tom R]

Re: the "Sunny f/16 rule...."

 

The results obtained by using any metering system depends upon the ambient light, e.g., what is f/16 in Texas is NOT necessarily f/16 in Northern England, etc., the type of film, e.g., chromes (color slides, positives) are much less forgiving than B&W negative films, such as TriX, the kind of processing, and, last but not least, the photographer's aesthetic intent.

 

I have used film Leicas for forty years (M2, M4, etc.) with the occasional use of hand-held light meters---precisely for those situations where exact, multiple readings were necessary.

 

Where you place the settings on the back of the M2 obviously have no effect on the exposure you will obtain. If your film is rated (on the box) at 100ASA, then meter for 100 ASA. Using the "sunny 16 rule" that might mean starting at 1/125 @ f/16. I say "might" for all of the reasons listed in the first paragraph. Perhaps you need a shallower depth of field? If so, adjust accordingly. It might turn out that based upon your processing, that exposure gives negatives that are too dense ... You get the idea.

 

If you have access to a light meter, then record the incident exposure reading and keep records on your actual settings for that kind of scene. If you do this every day, with the same film, etc., you'll quickly acquire a sense of what works ... at least for that kind of scene. It sounds hard, but it isn't. If you change only one variable at a time, in a short time you'll have a pretty good sense of how to expose that film in a variety of settings.

 

Have fun ... .