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Exposure variables question


kenneth

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This lunch time I took a photograph of my wife sat in our dining room which faces north. Film FP4 125 asa . First shot incident light metered Sekonic L398a 5.6 at 60th. Second shot camera metered M6- 75mm Voigtlander 2.5 at 15th of a second. Would you expect such a variation in the two readings. Subject in even light without overcast day?

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This lunch time I took a photograph of my wife sat in our dining room which faces north. Film FP4 125 asa . First shot incident light metered Sekonic L398a 5.6 at 60th. Second shot camera metered M6- 75mm Voigtlander 2.5 at 15th of a second. Would you expect such a variation in the two readings. Subject in even light without overcast day?

 

It's entirely possible, Kenneth. Bear in mind that the incident angles (angles of incidence?) of the handheld meter versus the M6 TTL meter through the relatively narrow FOV of the 75mm lens (31 degrees if I recall correctly) can account for such a difference.

 

In other words, the incident meter is much more affected by ambient light than the narrowly "focussed" reflected reading taken through the 75mm lens. This is why to this day I have a soft spot for the multi-spot metering capability of the old OM4ti.

 

Which of your readings is "correct"? I'd venture to suggest that it is the one that gives you the effect you are seeking, or in other words that produces a result that is closest to your "vision" of the scene.

 

Regards,

 

Bill

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Thank you Bill, I wondered whether there was a metering problem with my M6. I am on my first roll of film with it so as yet I do not have anything to compare. The Sekonic meter is brand new so I assume there cannot be a fault in that. I obviously have a lot to learn which is why I value the knowledge base available here. I took the shot on both settings so I can compare the results when I get them back from Ilford processing-

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G'day Kenneth,

 

I reckon that it's worth getting a tiny bit scientific here in order that you more quickly get to taking photographs that please you.

 

Just briefly put the handheld meter back in its case and leave it there.

 

Then get a fresh roll of film and methodically work through a series of shots - gentle overall light, backlit, front lit etc. For each shot take first a frame at whatever the M6 meter tells you and then bracket by half stops - -1/2, -1, +1/2, +1. Sometimes it helps to have little signs to put in the shot so that you have reference to what the exposure was.

 

When the shots come back you can then begin to form a view of what pleases you and in which situations. It will introduce some clear personal rules which will help you get more good frames.

 

Later you can introduce the handheld meter through a similar process - including incident vs reflected.

 

My apologies if I am trying to teach Grandma how to suck eggs.

 

Regards

 

Mike

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My apologies if I am trying to teach Grandma how to suck eggs.

 

Mike, not at all, I value your comments. I used an early Weston back in the days of my Nikon F. I then ventured into attached metering with a Pentax S1a, continued into ttl with a Spotmatic F. Went back to my Weston with a Leica 111. Latterly I have come to rely on the cameras built in meter, mainly for mountain photography with an OM2n right up to my last camera which was a Nikon FM2n. It is only now, that I want to pursue my photography a little further, hence the M6. I also want to do some street photography and the idea of a hand held meter seemed a good idea to avoid having to bring the camera up to eye level until the last minute. I will work through your suggestions- thank you

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If you use the incident meter correctly – at or close to the subject, aimed at the camera – it will in effect give you a value based on the diffuse highlights (the white dome IS an artificial diffuse highlight) corrected to give a correct mid-tone and highlight value. Never a burned out highlight (light sources and specular highlights are a different matter and are allowed to burn out of course). And this is just the exposure we want with slide film and digital, which have no exposure latitude, and where you have to let deep shadows take care of themselves in order to save the highs. With neg film you have more slack of course, but an incident metering will still be optimal for most purposes.

 

I do not leave home without an incident meter. The situation you described is most likely one that overtaxes the latitude of any film, but in that case, aiming for correct diffuse highs in the subject will be best in any case.

 

The old man from the Age of Selenium Meters

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As a quick check - if you point the M6 at a sheet of white paper (fill the frame) and take a meter reading, then compare with the incident meter reading in the same light. If the M6 is OK it should be about 3 stops under the incident meter reading. If you have a grey card, then you can compare directly.

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Assessing your exposure 'correctness' from any prints done by a lab will mislead you. I venture to say that the print from the M6 meter will 'near as damn it' match the print from the incident meter. The reason is that the labs automatically 'adjust or balance' the print exposure to be 'normal' regardless of whether you want it over or under exposed. The only way to more accurately assess the difference is by studying the negative, also allowing for the processing it is subjected to!

 

Life gets more "interesting" as you dig deeper.:D

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As a quick check - if you point the M6 at a sheet of white paper (fill the frame) and take a meter reading, then compare with the incident meter reading in the same light. If the M6 is OK it should be about 3 stops under the incident meter reading. If you have a grey card, then you can compare directly.[/quote

 

David- Thank you for the above also thank you for the links to your photographs they terrific, almost LS Lowry like, great composition and superb light. What lens were you using on your Leica?. With regards to the metering I guess from the example quoted on my original post the difference between M6 meter and Sekonic meter is about 3 stops so David which of the two readings would you then adopt for exposure? Sorry to seem so dumb

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The advice about the white sheet of paper is about right for neg film. For slides and digital, about 2.5 stops is right. When shooting in snow, where a reflected-light meter may be gravely misled into underexposure, the trick is to switch over to manual, meter the snow, and then increase the exposure by 2.5 stops – a little more in the sun, a little less if the sky is overcast.

 

But a quick incident check is easier.

 

The old man from the Age of Selenium

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Having spent £120.00 GBP on a new Sekonic Light Meter to find that it bears no correlation to the meter on my M6 I am planning to return it today and buy an old Weston Master V that the retailer was not keen to sell me because he did not think it was as accurate as the Sekonic. Providing the Weston is consistent then I can take readings with it and make adjustments as I would with the Sekonic and save some money as well. Thank you all for your input in this query

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You were using the Sekonic correctly weren't you? I.e. metering from where your wife was sat with the white dome on the meter pointing back towards the camera.

 

If you were using it like you'd use a reflective meter - from the camera position pointing it at your wife - I could understand big discrepancies between the camera and the hand held meter.

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Having spent £120.00 GBP on a new Sekonic Light Meter to find that it bears no correlation to the meter on my M6 I am planning to return it today and buy an old Weston Master V that the retailer was not keen to sell me because he did not think it was as accurate as the Sekonic. Providing the Weston is consistent then I can take readings with it and make adjustments as I would with the Sekonic and save some money as well. Thank you all for your input in this query

 

Kenneth, hold hard. I think you are getting ahead of yourself. Steve is right; if you are using the Sekonic correctly you should get the same readings as you would with the Weston.

 

Put the Sekonic away, and use the M6 with it's built in meter for a few rolls. Shoot slide, so that you can see what is happening without interference, and take some exposure notes. Work out what works for you and what doesn't.

 

Regards,

 

Bill

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I took the Sekonic Meter back this morning for a refund and bought the Weston Maser V complete with invercone. I took the camera onto the high street in the center of Leeds and guess what. Both camera and meter gave identical readings. In passing, another thing I did not like about the Sekonic was that it was very easy to inadvertently snag the ISO slide when putting the meter back into the case. Not a problem with the Weston as you have to press a button to change the ASA settings and also I am familiar with it having had one years ago- Thank you all

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