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12-15-2013, 10:35 AM   #1
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Manual Focus lenses w/Interval Photography

I was doing some interval photography and was unhappy to see how blurry the pictures were. I discovered that in Av/auto ISO mode the camera was changing the manually set f-stop to wide open. Reading on the forums, I found that you can tape over the contact points to the lens and keep your f-stop. I did this and it worked. My question is this: Under this scenario how is the camera setting the exposure and ISO? Automatically, and generally correct? I can't setup the camera in full M exposure mode, because with interval shooting the light conditions change over time and I'd prefer if the camera adjusted automically. But because it is always shooting landscapes, I think f8 will be fine for sharpness..

12-15-2013, 11:03 AM   #2
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The tape over the contacts lies to the camera, and it thinks there is an A setting on the aperture, and that you have set a specific aperture. The exposure variations are due to the metering. the ratio of light to dark will change as the shadows change.
12-15-2013, 11:13 AM   #3
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What model camera are you using? By taping over the contacts you are basically using the lens like a M42 lens ( I assume you are using a non "A" lens) = stop down metering, and depending on the body you are using the metering may be more or less off/pernickety. My K-r is hopeless, I am typically compensating by 2-3 stops.


Scrap that. I don;t see how you are stopping the camera holding the lens open in Av mode: the only way out of that that I know of (with a PKM mount lens) are the hacks mentioned here. perhaps you can elaborate....

However with regard to M42 et al lenses in Av mode, taking some test shots and checking it out is a must. However once you have ~ correct compensation dialed in you should be set.

There are a lot of posts on using M42 lenses, and exposure issues..

Last edited by marcusBMG; 12-15-2013 at 11:20 AM.
12-15-2013, 11:16 AM   #4
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QuoteOriginally posted by Canada_Rockies Quote
The tape over the contacts lies to the camera, and it thinks there is an A setting on the aperture, and that you have set a specific aperture. The exposure variations are due to the metering. the ratio of light to dark will change as the shadows change.
Well, that sounds like doing this gives me what I want then, no?

12-15-2013, 11:16 AM   #5
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QuoteOriginally posted by marcusBMG Quote
What model camera are you using? By taping over the contacts you are basically using the lens like a M42 lens, = stop down metering, and depending on the body you are using the metering may be more or less off/pernickety. My K-r is hopeless, I am typically compensating by 2-3 stops.

Taking some test shots and checking it out is a must. However once you have ~ correct compensation dialed in you should be set.

There are a lot of posts on using M42 lenses, and exposure issues..
A k01 with 28mm smc manual focus lens.
12-15-2013, 11:22 AM   #6
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QuoteOriginally posted by joflaig Quote
A k01 with 28mm smc manual focus lens.
Not familiar with K01, may operate different to eg my K-r. see my edit 1st post
12-15-2013, 11:23 AM   #7
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QuoteOriginally posted by joflaig Quote
Well, that sounds like doing this gives me what I want then, no?
With photography, use whatever works. If you shoot RAW, the exposure variations between the images can be corrected with less loss to image quality than with JPEG.
12-15-2013, 11:34 AM   #8
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QuoteOriginally posted by marcusBMG Quote
What model camera are you using? By taping over the contacts you are basically using the lens like a M42 lens ( I assume you are using a non "A" lens) = stop down metering, and depending on the body you are using the metering may be more or less off/pernickety. My K-r is hopeless, I am typically compensating by 2-3 stops.


Scrap that. I don;t see how you are stopping the camera holding the lens open in Av mode: the only way out of that that I know of (with a PKM mount lens) are the hacks mentioned here. perhaps you can elaborate....

However with regard to M42 et al lenses in Av mode, taking some test shots and checking it out is a must. However once you have ~ correct compensation dialed in you should be set.

There are a lot of posts on using M42 lenses, and exposure issues..
I put tape over the contacts, and it worked. I can look at the aperture when shooting and it stays where set, instead of opening up all the way.

12-15-2013, 11:38 AM   #9
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QuoteOriginally posted by joflaig Quote
I put tape over the contacts, and it worked. I can look at the aperture when shooting and it stays where set, instead of opening up all the way.
Can you refer me to the posts that told you about this I am curious...
12-15-2013, 11:51 AM   #10
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Yes, if you use a manual lens, the camera only allows M and Av mode. In Av mode, it meters continuously and allows auto-ISO, but it always shoots wide open. In M mode, you need to use green button to meter and ISO must be static, but the camera will (At least try to) stop down the lens to the selected aperture (which you select on the aperture ring, you must enable its usage in the back of the menu).
What you are talking about is a little hack that gives the camera some more automation. Another trick is to push the lens mount button and twist the lens off a little, just so that it doesn't lock.
Um, I think the camera, if in Av mode, will then meter automatically and continuously. You can try a small test with 5 exposures and simply turn off the lights or put your hand over the lens to see how it adjusts.
12-15-2013, 12:01 PM   #11
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QuoteOriginally posted by Na Horuk Quote
Yes, if you use a manual lens, the camera only allows M and Av mode. In Av mode, it meters continuously and allows auto-ISO, but it always shoots wide open. In M mode, you need to use green button to meter and ISO must be static, but the camera will (At least try to) stop down the lens to the selected aperture (which you select on the aperture ring, you must enable its usage in the back of the menu).
What you are talking about is a little hack that gives the camera some more automation. Another trick is to push the lens mount button and twist the lens off a little, just so that it doesn't lock.
Um, I think the camera, if in Av mode, will then meter automatically and continuously. You can try a small test with 5 exposures and simply turn off the lights or put your hand over the lens to see how it adjusts.
That's what I thought. Seems to work like a charm.
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