I bought a 5x7 wood field camera probably a year ago and never took a picture with it. I want to buy film but I don't have a meter so I was going to use my Canon 6D as the meter. I started reading a little about exposure factor with bellows extension and started thinking. Now here is the stupid question. Is there any reason why I can't use my 6D as a meter looking through the bellows with the back off? I would be looking through the lens and wouldn't the sensor be seeing the same amount of light as the film after bellows extension?
Stupid question?
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A
- Thread starter campy51
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I don't it will work, you want to meter at your working F stop, for a 5X7 maybe F 22 to 32, but your digital camera will be metering wide open, maybe if you meter wide open and the 5X7 is wide open, then just calculate the correct stopped down aperture? I would look at Shopgoodwill.com and buy a Weston or GE meter.
This just isn't going to work. The meter on the D camera would be looking through two lenses. It won't operate without a lens on it.
It's a hack and won't be perfect, but you can use a another camera's meter, but not thru the LF lens,
just look at the scene, try to compose the same.
It'll kind-of-work, err on the side of overexposure... add a stop to the recommendation...
For LF, you'll want a spot meter eventually, slippery slope and all that
just look at the scene, try to compose the same.
It'll kind-of-work, err on the side of overexposure... add a stop to the recommendation...
For LF, you'll want a spot meter eventually, slippery slope and all that
I would use your 6D as a meter as normal, then download an app for your smartphone to calculate the extension factor. I will estimate the extension factor if I want a quick answer. That gets me within 1/2 stop or better of the correct factor.
You can take values measured with the normal focal length on the Canon for normal focal length with the 5 × 7 camera which is 8¼ inches or 210 mm. No bellows extension compensation needed
See I was right, it is a stupid question.
Thanks everyone.
Thanks everyone.
MattKing
Moderator
Sinar (and possibly a few others) made a meter that you could use to take spot readings off of the ground glass.
It might be possible to create some sort of Rube Goldberg setup using your 6D and a rubber lens hood to do something similar.
But I expect the result would just not make much sense.
It might be possible to create some sort of Rube Goldberg setup using your 6D and a rubber lens hood to do something similar.
But I expect the result would just not make much sense.
You do know that you only need a bellows extension factor for close-up work, don't you? For "normal" landscapes and portraits you can just use the metered exposure. As a rule of thumb, you don't need to worry about bellows extension factors till the total bellows extension is 125% of the lens' focal length or greater.
Your D!&!?@L camera will work just fine as a meter, it's just not as convenient as having a dedicated meter. Just get a base exposure, adjust it for the aperture you want to use (add filter and bellows factors and reciprocity failure adjustments if you need any of these) and shoot away!
Best,
Doremus
Your D!&!?@L camera will work just fine as a meter, it's just not as convenient as having a dedicated meter. Just get a base exposure, adjust it for the aperture you want to use (add filter and bellows factors and reciprocity failure adjustments if you need any of these) and shoot away!
Best,
Doremus
Not a stupid question at all and the answers provided will help others.
Enjoy your 5x7!
Why not just download one of the light meter apps for your phone. It's a lot lighter than carrying around your 6D, and at least as accurate as an old Weston or GE meter.
Bellows factors are typically only used for close-ups, so for typical work you can probably ignore them--certainly you can ignore them for landscape work.
At 1:1 ratio (i.e., film image size is the same as the subject), the bellows factor is 2 stops. Bellows factors can always be calculated, and don't need to be metered, but you can always guesstimate.
At 1:1 ratio (i.e., film image size is the same as the subject), the bellows factor is 2 stops. Bellows factors can always be calculated, and don't need to be metered, but you can always guesstimate.
I'd like to second what faberryman said about using an app on your phone - it's a really handy light meter, and plenty good enough until you decide you want a proper spot meter for zone system work. As for bellows extension compensation, I like the little tool from Way Beyond Monochrome, as found here: http://www.waybeyondmonochrome.com/WBM/Library_files/TemplatesEd2.pdf
Light is light, it does not matter if its being reflected onto onto your optical sensors, a camera's electronic sensor or chemical based sensor, nor does it matter what size the sensor is.
To use a camera with a built in light meter to meter a scene for use on a different camera the built in meter camera must have a normal focal length lens, not a zoom or telephoto.
Lens used in large format, 2x3 and up, the lens will focus from infinity to the lens closest focusing distance in approximately 1/3 of the lens focal length from its infinity position. Beyond that the lens will require a double or triple the distance from the close distance to focus to the next closest foot from the film plane. 1/3 of the lens focal length when applied to bellows extension formulas equals less than 1/3 stop of additional exposure from infinity position.
Using post 6 statement of 210mm being normal for 5x7 210/3=70mm. Lets say, for the sake of argument, the lens focuses 10 feet at 65mm extension from infinity but will not focus 9 1/2 feet until 95mm from infinity then 10 feet will be considered the lens close focus distance.
An exposure error of 1/3 stop or less will not be noticeable for all practical purposes including making high end gallery/fine art prints.
To use a camera with a built in light meter to meter a scene for use on a different camera the built in meter camera must have a normal focal length lens, not a zoom or telephoto.
Lens used in large format, 2x3 and up, the lens will focus from infinity to the lens closest focusing distance in approximately 1/3 of the lens focal length from its infinity position. Beyond that the lens will require a double or triple the distance from the close distance to focus to the next closest foot from the film plane. 1/3 of the lens focal length when applied to bellows extension formulas equals less than 1/3 stop of additional exposure from infinity position.
Using post 6 statement of 210mm being normal for 5x7 210/3=70mm. Lets say, for the sake of argument, the lens focuses 10 feet at 65mm extension from infinity but will not focus 9 1/2 feet until 95mm from infinity then 10 feet will be considered the lens close focus distance.
An exposure error of 1/3 stop or less will not be noticeable for all practical purposes including making high end gallery/fine art prints.
I'm an LF film guy, use spot and incident meters, but realism shows the meters on my (and wife's) DSLR cameras are very accurate, as is the meter on mt YAshicamat 124, it's knowing how to use different metering systems and not letting them fool you.
It's very esay with experience, quite daunting otherwise.
Ian
It's very esay with experience, quite daunting otherwise.
Ian
Meter with the electric camera, then set f-stop with correction for bellows extension. Done deal.
If you are experimenting, it's all part of the learning process. If you want full-performance results, pay full price for a real meter and learn to use it.
If you are experimenting, it's all part of the learning process. If you want full-performance results, pay full price for a real meter and learn to use it.
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