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07-03-2014, 10:33 AM   #1
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A Q10 image and a question about sensors

Below is a photo I took last night with my Q10. I picked up one of the $20 adapters and mounted the Minolta Rokkor MC 50mm 1.4 lens I acquired with my first SLR back in the '70's.

I have to say I'm pretty pleased with the potential. I had a friend who shots with a full frame camera say it makes him miss the reach that the smaller sensors provide. Which leads me to my question.

Is the "reach" really greater considering that the image size/sensor is smaller. Put another way, would you get the same size image using a similar lens on a full frame and then cropping down to the proportionate size of the Q10 sensor?

Since the image size projected by the lens is fixed, so to speak, it would seem that the real key is the pixels density. Do cropped sensors like that on the Q cameras have a higher density of pixels per square milliliter?

And lastly how much, if any, of the 5.5X factor the result of the adaptor acting like a bellows and moving the lens further out.

I'm really enjoying the Q10. I picked it up on Amazon a couple of weeks ago for $169 thinking I would keep it close by and also so that my wife can play with it while I'm using my K-50. She loves to take sunsets using her iPhone so I'm hopeful the photo like the one below will inspire her a bit.




Last edited by TedW; 07-03-2014 at 10:38 AM. Reason: misspelled title
07-03-2014, 11:17 AM   #2
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QuoteOriginally posted by TedW Quote
Is the "reach" really greater considering that the image size/sensor is smaller. Put another way, would you get the same size image using a similar lens on a full frame and then cropping down to the proportionate size of the Q10 sensor?
I have done the test back when I got my Q (original Q, same sensor as your Q10) comparing with a K5 (APSC). What I came up with was that using the same lens (vivitar 200) in the same condition, cropped pictures from my K5 were a bit sharper and had less noise than the ones from the Q but only marginally. So it was pretty much a tie.

But when I got my K3, I repeated the tests and this time the cropped K3 pictures are much, much better than the one from the Q, again in the same conditions, using the same M42 lens.

However the shots from the Q were still good and didn't need to be cropped in post. And in some case, the greater depth of field of the Q can be an advantage.

If you compare the Q to a FF camera, which will need to be cropped in a bit further, the results may vary and probably in favour of the Q. But since I don't have a FF camera, this is speculation.

QuoteOriginally posted by TedW Quote
Do cropped sensors like that on the Q cameras have a higher density of pixels per square milliliter?
Yes, less area, so density has to go up (for the same number of pixel).

QuoteOriginally posted by TedW Quote
And lastly how much, if any, of the 5.5X factor the result of the adaptor acting like a bellows and moving the lens further out.
Not at all, the lens is further out compared to a Q lens but it is at the proper flange distance for the adapted lens (distance from the mount to the sensor). So your minimum focus distance and your infinity focus are correct with an adapted lens. Typically a bellow is to extend the flange distance affecting MFD and/or infinity.
07-03-2014, 11:23 AM   #3
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It's true that smaller sensors basically do the same thing as cropping a photo from a larger sensor to just the center part. However, it's also true that the pixel density on the Q sensors (even the Q7 which has the lowest pixel density) is higher than many larger sensors. To find out the pixel density of any particular sensor, you have to divide the total pixels by the area of the sensor.

The lenses are not moved farther out than they would be on the cameras they are made for when shooting on a Q. Moving the lens further away from the sensor than its registration distance on any camera would do the same thing; you would lose infinity focus while gaining closer focus (just as though you put it on bellows or an extension tube on the camera it was made for). The crop factor is entirely about the sensor size, not the distance from the sensor.
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