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View Full Version : Crop factor: FS100 vs. 7D



colby_gottert
07-08-2011, 03:23 PM
I recently put a 35mm nikkor lens on my FS100 through a Bower F-mount to E-mount adapter. When comparing the size of that image to a 35mm lens on the 7D, the image was much smaller on the FS100 than the 7D. My understanding is that the FS100 SUper35mm sensor is actually slightly larger than the sensor on the 7D (http://www.abelcine.com/articles/index.php?option=com_content&view=article&id=542:35mm-digital-sensor-comparison-chart&catid=24&Itemid=45), therefore I was surprised that the image on the FS100 was narrower. My questions are:
1. Does the FS100 have a larger crop factor than the 7D?
2. Does the Bower F-mount to E-mount increase the crop factor?

Any advice would be most welcome.

Thank you.

-Sandro-
07-08-2011, 04:37 PM
that's strange because the FS100 has a sensor slightly larger but not that large!

Barry_Green
07-08-2011, 05:10 PM
Not all lenses calculate focal length the same; one manufacturer's 35mm might equate to someone else's 38mm. But if you used the same lens on both, they should have looked almost identical. The 7D's sensor is 22mm wide, the FS100's is 23.6mm wide. Very little difference. Try them both with the same lens and you should see the expected performance.

jetswing
07-08-2011, 06:55 PM
The sensor on 7D is about 2 inch or so back from the mount vs less than an inch on FS100. If you don't line up the sensors, the test results might be off.

colby_gottert
07-08-2011, 07:23 PM
Thanks for the advice. I was anticipating the lenses to produce the same result, which is why I suspect the adapter might have something to do with the difference in image, but I will have to run a few more tests. I'll report and findings on the site.

Thank you.

LowDown
07-09-2011, 08:32 AM
The sensor on 7D is about 2 inch or so back from the mount vs less than an inch on FS100. If you don't line up the sensors, the test results might be off.
the distance from the back of the lens to the sensor has to be the same or you will not have infinity focus. The nikon adapter takes this into account. You should not see any difference in "crop factor".

SergeSmArt
07-15-2011, 01:02 AM
the distance from the back of the lens to the sensor has to be the same or you will not have infinity focus. The nikon adapter takes this into account. You should not see any difference in "crop factor".

"crop factor" of Canon cameras =1.6 .... Sony FS 100 crop = 1.5 ..and we talking about 24X36mm frame size as the base to compare view angle...

FelixGER
07-15-2011, 04:58 AM
"crop factor" of Canon cameras =1.6 .... Sony FS 100 crop = 1.5 ..and we talking about 24X36mm frame size as the base to compare view angle...

That seems to fit. When you watch the beginning of my video, you can see the different crop factors. Both cams were in identical positions and used the same lens.
http://www.vimeo.com/26242709

LowDown
07-15-2011, 07:16 AM
"crop factor" of Canon cameras =1.6 .... Sony FS 100 crop = 1.5 ..and we talking about 24X36mm frame size as the base to compare view angle...
I was referring to the question of whether the adapter could increase the "crop factor". Here the larger sensor should give you a wider image than the 7d but the op was seeing a tighter image.

Barry_Green
07-15-2011, 08:55 AM
The adapter cannot change the crop factor in any way. The sensor is what does the cropping, not the lens and not the adapter.

If the adapter is the wrong distance or something, that'll just change the ability to focus.

dcloud
07-15-2011, 09:15 AM
love the fact that the tiny crop still matters

Barry_Green
07-15-2011, 09:20 AM
love the fact that the tiny crop still matters
Yeah, the difference between them is a 1.53x vs. a 1.6x. Inconsequential at most.

colby_gottert
07-16-2011, 08:36 PM
Thanks, that was very useful to check out.