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08-13-2014, 11:10 AM   #1
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Crop factor for 8mm / super 8 cine lenses.

I'm looking at a 13mm cine lens for the Q but I'm wondering about other 8mm and super 8 cine lenses and how to determine their relationship to 35mm focal lengths. Thanks.

08-13-2014, 11:16 AM   #2
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The lens being for an 8mm camera originally has no bearing on crop factor -- 13mm is 13mm. Crop factor on the Q/Q10 is 5.6x and on the Q7 is 4.7x to convert to 35mm equivalent...
08-13-2014, 11:32 AM   #3
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It's the sensor that determines the crop factor, not the lens. Whether the lenses are worth using is another matter altogether.
08-13-2014, 12:18 PM   #4
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QuoteOriginally posted by vonBaloney Quote
The lens being for an 8mm camera originally has no bearing on crop factor -- 13mm is 13mm. Crop factor on the Q/Q10 is 5.6x and on the Q7 is 4.7x to convert to 35mm equivalent...
Thanks. So, a 13mm lens made for 8mm moviecam is equivalent to a 72.8mm lens on a 35mm camera.

QuoteOriginally posted by TER-OR Quote
It's the sensor that determines the crop factor, not the lens. Whether the lenses are worth using is another matter altogether.
I'm looking at some well regarded cine lenses from the 50's; shouldn't be a problem.

08-13-2014, 12:24 PM   #5
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QuoteOriginally posted by MD Optofonik Quote
Thanks. So, a 13mm lens made for 8mm moviecam is equivalent to a 72.8mm lens on a 35mm camera.
As is a 13mm lens for a video camera, or whatever. Point being it doesn't matter what it was "made for", only that it is 13mm.

However, the original format might be relevant because of vignetting issues -- 8mm frames are even smaller than the q sensor, so a lens made for that format might have an image circle so small that you'd get vignetting on the Q...
08-13-2014, 12:30 PM   #6
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As suggested above, a 13 mm focal-length lens is a short telephoto on the Q or Q7,

However, there is a more important thing to note. 8mm and Super 8mm are frame size designations. The diagonal measurement for both a standard 8mm and a Super 8mm frame is smaller than either the 1/2.3" Q or 1/7" Q7.
Image sensor format - Wikipedia, the free encyclopedia
C mount - Wikipedia, the free encyclopedia

So it is possible that a lens won't cover the full image circle of the sensor. It might, but you have no way to know in advance. So, even if you can get the mount to work out, you might wind up with an image with the corners cut off.

If it is made for one of the larger formats such as 16mm film, then it should cover the sensor just fine.

Oops, vonBaloney beat me to it.
08-13-2014, 12:33 PM   #7
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You're quite likely to get blurry edges even if the circle does cover it. Actually, you're kinda likely to get blurry whole image with an old 8mm lens...
08-13-2014, 12:51 PM   #8
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After a bit more research I discovered this but the same lens maker produced lenses for both formats so I've started looking at the 16mm versions. Thanks for all the insight.

08-13-2014, 04:21 PM   #9
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FWIW, this was taken using a Yashinon 13 mm lens on a Q7. You'll notice some vignetting in the upper left.

https://www.flickr.com/photos/benchan/14643440564/
08-13-2014, 11:46 PM   #10
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Based on my experience with vintage 8mm/super 8mm zoom len or prime lens, smaller focal length tend to vignette on Q. For example, 6.5mm prime d-mount lens generally four out of five lens will vignette on pentax Q. Similar things happen with 8mm zoom lens on 4:3 mode unless you do it on 16:9 or video mode. For super 8mm zoom, about 1/3 of them will vignette on wide end on 4:3 (less frequent then 8mm zoom) because they have bigger image circles. With that being say, it is extremely fun to mod a super 8 zoom len and adapt it for pentax Q. Crop factor of cine len for 8mm/super8mm should be the same as any other len (5.6x on Q and 4.7x on q7/q-s1). Modding lens from 8mm/super8mm is unique in and off itself because these zooms are of higher quality built, tend to have better lpm resolution, and CA correction on more expensive super8mm zooms.

Anyway, here are some of my modded lens from super8 camera for Q


Last edited by rendition; 08-14-2014 at 12:24 AM.
12-07-2015, 08:18 AM   #11
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QuoteOriginally posted by murrelet Quote
FWIW, this was taken using a Yashinon 13 mm lens on a Q7. You'll notice some vignetting in the upper left.

https://www.flickr.com/photos/benchan/14643440564/
I don't know why everybody where is about a tiny bit of been yelling are used to shoot with old toy cameras and then vignetting works under the right circumstances your picture looks great. . something greatest photography from the turn the century has vignetting and still looks great now
12-07-2015, 08:30 AM   #12
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QuoteOriginally posted by rendition Quote
Based on my experience with vintage 8mm/super 8mm zoom len or prime lens, smaller focal length tend to vignette on Q. For example, 6.5mm prime d-mount lens generally four out of five lens will vignette on pentax Q. Similar things happen with 8mm zoom lens on 4:3 mode unless you do it on 16:9 or video mode. For super 8mm zoom, about 1/3 of them will vignette on wide end on 4:3 (less frequent then 8mm zoom) because they have bigger image circles. With that being say, it is extremely fun to mod a super 8 zoom len and adapt it for pentax Q. Crop factor of cine len for 8mm/super8mm should be the same as any other len (5.6x on Q and 4.7x on q7/q-s1). Modding lens from 8mm/super8mm is unique in and off itself because these zooms are of higher quality built, tend to have better lpm resolution, and CA correction on more expensive super8mm zooms.

Anyway, here are some of my modded lens from super8 camera for Q
great information but I can't see the picture can you email to me Terrence 5050 @ Yahoo
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