SLR as a Light Meter

I am about to use a medium format camera that does not have a built

in light meter.

 

I do have a Nikon SLR that has a meter built in. Instead of buying

a seperate meter, I thought I could use my Nikon's.

 

The lens on the medium format camera is 75mm (45mm equivalent for a

35mm camera). I was wondering if I take my Nikon and zoom my lens

to 45mm, and then take a meter reading, whether I could then use

this reading for my medium format camera.

 

I also heard if you use an 18% reflective gray card, zoom in with an

SLR so the whole image is of the card, and take a reading that way,

you can get an accurate meter reading. Any comments on this

technique?

 

I appreciate any help I can get on these issues. Thank you.

You're right on track. I used to have do this all the time when I first got my 'blad. You only need the grey card if you're in tricky situations or intentionally practicing the zone system, other wise, just trust you Nikon meter if you're familiar with it.

Reflected light metering is a bit of a strange concept to me -- take an arbitrary scene, and try to reduce it or a part of it to 18% grey, and hope that you picked the right set of tones to so convert.

 

I've generally used incident light metering -- it is reliable, and a more straightforward concept -- adjust the camera to the light conditions, not to the subject's reflectivity. Let the dark objects come out dark, and the light ones light... This only breaks down when you have extreme reflections, or direct, non-incident light. Then, you'd also have trouble with reflected light readings.

 

It's a bit awkward too, but once you have the lighting condition down for an area, you can keep the same settings or vary them as needed and forget about the meter.

 

So yes, a grey card reading can be used for a reference. Moreover, you might find that the palm of your hand, when there aren't strong reflections, can be a very simple and, um, handy substitue for a grey card with a little manual adjustment / calibration.

 

Using a second camera as an incident light meter can also reduce the hassle -- essentially, you won't meter for every shot, just for the lighting -- angles and shading.

 

Putting away the meters should also be good exercise in light awareness.

 

And no, this is not a incident vs. reflected call to arms, merely an indication that incident light metering works for me. Obviously reflected works too.

I do this all the time with my Pentax ME super and Rolleiflex. It's not the most convenient way in the world. Before I got my rollei I often just set the ME super on aperture priority, except when on a tripod. Having to translate the readings to the Rollei gives me a better sense of what actual shutters and apertures I'm using in certain lighting conditions. Combining this method with knowledge of the sunny 16 rule i'm slowly becoming able to accurately guess exposure.

The SLR light meter / gray card apparatus seems like a nightmare. Plus you will never get the results you think you will. With reflected light metering that is present aboard the SLR, bright white objects will appear light gray, and black objects will appear dark gray. Also check out the Sekonic website for more examples.

 

I never thought I would be one to carry around a light meter, but now that I switched I will never go back to reflected light metering. I use a Sekonic. Your life will be easier if you get one of these and leave your Nikon and gray-card at home. It's the truth.

Using reflective metering off a grey card is equivalent to using an incident meter.

Sorry, but I feel grey cards and incident metering is a last resort. For whatever reason we might not want accuracy, but if we do, then for B&W negatives (5 stop exposure latitude.. aprox), meter the shadows and close by two stops. (This is because we want detail in the shadows and can develop to keep detail in the highlights). For Positive (slide) film you should generally meter the highlights and open two stops. (This film also has a poor exposure latitude). For slides I want some detail in the highlights and am willing to lose it in the shadows (Remember, we are usually projecting it). I am being deliberately general here as sure there are some shots that will demand a different metering than I describe, but I believe this technique to be more accurate a way of putting the image on the film. Now, what do I do for colour negative film? It has a very wide exposure latitude and so I expose for the shadows, close two stops and let the film maintain the highlights. I just read this back and I sure sound like an exposure geek lol.

hahaha... so use your slr as your meter and do the above..

Get an incident meter, DB. Aside from the awkwardness involved, your % of accurate exposures will be the same for the MF as it is for your Nikon. Reflective meters are typically fooled by backlighting and/or highly reflective surfaces.There's also the issue of flash metering, a built-in feature of several modestly-priced incident meters(e.g., Sekonics). After several rolls of inconsistent exposures, a handheld meter starts to make sense.

I use a Sekonic lightmeter meter in the incident mode and have a high success rate.

 

This may be down to the fact that I have never really understood when using an SLR meter I need to meter the shadows and then close down two more stops. Surely this is letting less light into the dark areas. I am sure there is an answer but it escapes me so I stick to the Sekonic.

 

Thank you for an informative forum.

 

Peter

"<I>I also heard if you use an 18% reflective gray card, zoom in with an SLR so the whole image is of the card, and take a reading that way, you can get an accurate meter reading. Any comments on this technique?</I>"<P>

 

That is basically what an incident meter will do, give you those results and quickly. Besides, it looks real cool hanging around your neck as you walk along the beach talking in your cel phone. "I have that shoot for GQ tomorrow. Tell Sergio he'll have to wait; I haven't found just the right model yet."

The SLR will work just fine as a reflected light meter. If it doesn't have a spot meter, you can put a long lens on it and make one. Since few lenses are exactly as fast as advertised, you may wish to take readings of a plain object with several lenses, noting any difference in the suggested exposure values.

 

I don't quite understand all the fretting about exposire compensation. Anyone using a MF camera probably knows how to meter and place subjects on the exposure scale. If not, check out Adam's "The Negative" from the library; it's one of the clearest tutorials on (zone based) exposure.

 

-Greg

The question of using a slr as a meter is just a question of

convenience and money. My idea of convenience is to have a

hand-held spot meter in my pocket so I can measure the light

range in a potential subject without getting into my camera bag

and setting something up. It certainly isn't to carry an entire slr

system to do something that a meter that weighs next to nothing

and will slip in a pocket will do instead. Other than that there's

no reason why you shouldn't use it after a test roll to make sure

that your new MF camera gives exposures much like your Nikon-

it's not unknown for apertures or (more likely) shutter speeds to

differ.

 

About the type of hand-held. Lots of people here seem to be

rushing you towards Incident metering without understanding

what sort of photographs you make and what type of film you

use. That's not right.. Incident metering is fine if you're taking

portraits, doing studio work, or outdoors with subjects you can

walk right up to and around. If you're taking scenics or any other

subject you're not right next to. incident metering is far from the

best way to meter and will often deliver worse results than using

your Nikon would provide. Even your Nikon will no doubt have a

"matrix" or similar meter pattern that takes multiple readings and

takes into account the range of brightness in the scene in the

exposure setting it selects/recommends. Incident metering

doesn't do that at all, and especially if you use slide film has

important weaknesses.

 

To use a grey card properly you need to angle it right vs the light.

It is not a simple thing to do if you want to have consistently

accurate exposures. If you master this it will be as useful as an

incident meter. Seems a complicated way to get somewhere

you may not need to be.

I did a test this afternoon using my Gossen Lunasix 3 in incident mode and reflective

mode (from a grey card). I got some interesting results. I've posted them to my portfolio if

you want to look. The incident reading, using the cone fitted (pointing directly backwards

from camera) was 250@F11 and the grey card (pointing from subject to camera) was 90/

F11. The film is FP4+ 120 (6x7) souped in Rodinal 1+50 for 13 mins at 20c. Hardware Fuji

GW670III. The difference in exposure is profound and the incident shot is too contrasty by

far. The grey card is softer and is much easier to print. BTW, The grey card matched

shadows -2.5 stops.

Interesting, John. Why is your incident meter shot so underexposed?

Is something wrong with your Gossen? Even the graycard (at shadow +2.5) seems a bit underexposed. When you spotmetered on shadow,

was it one of the dark leaves?

It's probably the scan Bill. The neg for the grey card look very good under a lupe. I agree

that the incident reading is under exposed though, but expected it. Very contrasty

situation and the type of picture that incident reading, IMHO, don't do well with. The sun

was right behind me and strong. This would have worked with slide film but not for

negative. Interestingly, the Rodinal has done a pretty good job of keeping the highlights

under control.

The sunny 16 rule with FP4+ 125ISO would call for 250@F11.

What you intend to do will not only work, but will work well and save you the cost of buying a new meter. It can be inconvenient, but not as bad as many would have you believe.

 

I have been using my 35mm Canon to meter for 4x5 chromes for over 2 years, and it works fine. There is a learning curve, that you can overcome with one roll of film. Meter a mid-tone, bracket by half stops, take notes. Do this in various lighting situations, Develop and evaluate. Now you have a base line for exposure using the meter from your 35mm.

 

I shoot both 35mm and 4x5, and have not felt the need to buy a hand held meter.

As many people are advising you to go out and buy a light meter (though that's not really necessary), I thought I'd add another suggestion -- get a (small, old, used) digicam that has a histogram support and ideally manual exposure settings. Many of the other attributes -- esp. MP size, don't matter too much in this usage. Effective focal length range will matter. Unfortunately, this won't get you a flash meter (which is probably a feature that significantly raises the prices of incident meters). To deal with that minimally, you'd need one with a hot shoe or sync terminal. In addition, the digicam will have a more limited dynamic range, and its "ISO" would need to be manually "calibrated" to your film camera's, but these are minuses that are compensated by other potential advantages.

Nothing wrong with using another camera's TTL meter to support a meterless camera. I did that for a while using my Canon T70 as a meter for my Rollei TLR. Worked very well and it was handy having a backup camera loaded with different film for different circumstances.

 

You can turn an SLR's TTL meter into a surprisingly accurate incident meter by using a cheap white styrofoam coffee cup. Pop it over the lens, aim toward the sky (or other light source) and use that meter reading. The white styrofoam diffuses the light just like the dome (or flat) diffuser on an incident meter.

 

Since then I've sold the T70 and got a Minolta Autometer IIIF incident meter and Pentax Spotmeter V, but the TTL meter with coffee cup worked just fine.

 

The idea to use a digicam's meter can work too. I've tried my Olympus C-3040Z digicam for metering with film and it works quite well, especially in multispot mode. The digicam has about the same dynamic range as Velvia so it's useful for relative metering situations. I don't know whether other digicams would work but they're worth a try.

When I first got my Yashica D (MF TLR) I used my Rebel 2000 as a big, expensive, heavy lightmeter for a couple months, until I screwed up the conversions enough times. Considering all the factors that were coming into play sometimes, such as different film speeds, filters on one or both camera, and exposure compensations, it was just too much of a hastle. So I went over to eBay and got a $5 lightmeter that was made around the same time the camera was. It's just about as accurate as the Rebel (with the exception of especially light or dark situations), gives a more authentic feel with the old camera (if that's what you're going for--it feels nice for me) and is a hell of a lot easier to use. You don't have to spend hundreds of dollars on a fancy light meter; a simple one will do the trick.

I too just started shooting in medium format - mamiya 645. I have been using my nikon f-100 for spot metering and using the zone system as advocated by Ansel Adams in The Negative and exposing the dark areas I want any detail in on zone II - just as the book recommends. I have also tried using the matrix metering in the f-100 but find that despite the greater time consumpion and mental work required, using the spot metering and zone system works better for me.