Camera Sensor Size

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Fred R
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Camera Sensor Size

Post by Fred R » Tue Feb 25, 2014 7:16 pm

When shooting a multiple image photo is there an advantage to use an APC sensor sized camera instead of a full frame sensor camera? I realize that the APC sensor would require more images for the same field of view but would the image edges be any sharper because of the sensor size is using less of the lens image circle?

Thanks,

Fred R

maxlyons
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Re: Camera Sensor Size

Post by maxlyons » Wed Feb 26, 2014 9:06 pm

I don't own a full-frame camera, so I would be interested to hear what others think about this as well. However, I have looked at a lot of MTF charts for lenses, and my guess is that the answer to your question probably depends heavily on the specific lens that you are considering. When I look at MTF charts for most lenses, it seems like most are more consistently sharp across an APS-C sized sensor compared to full frame. Of course, full-frame cameras are less "pixel-dense" than APS-C cameras (at least, that's true of most of today's models) and you get other benefits using full-frame. Additionally, some full-frame lenses are sufficiently good that this is probably only a theoretical problem. But, my guess it that unless are investing in really good quality lenses, images from an APS-C sized camera might appear more uniformly sharp compared to those from a full-frame camera.

And, uniform sharpness is quite an important consideration when stitching panoramas. Vignetting and distortion are largely correctable using software, but if you have a lens with soft edges, then the final panorama will show a repeating transition from sharp to soft to sharp to soft across the scene, unless you crop a lot from the edges of the images. But, if you are going to do that, why not just use an APS-C sensor?!

Max

Fred R
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Re: Camera Sensor Size

Post by Fred R » Wed Feb 26, 2014 10:43 pm

That makes sense to me. I am currently shooting with a Canon 24-105 f/4 L zoom lens on a Canon 1Ds Mark ii. I can definitely see soft edges at the 24 mm setting. Perhaps if I am shooting at a more middle zoom range such as 40-60 mm I won't see as much. I will need to give it an extensive test.

Fred

sarakhan
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Re: Camera Sensor Size

Post by sarakhan » Tue Dec 09, 2014 12:00 pm

When shooting a multiple image photo is there an advantage to use an APC sensor sized camera instead of a full frame sensor camera? I realize that the APC sensor would require more images for the same field of view but would the image edges be any sharper because of the sensor size is using less of the lens image circle?



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linda00145
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Re: Camera Sensor Size

Post by linda00145 » Sat Oct 03, 2015 7:37 am

Fred R wrote:When shooting a multiple image photo is there an advantage to use an APC sensor sized camera instead of a full frame sensor camera? I realize that the APC sensor would require more images for the same field of view but would the image edges be any sharper because of the sensor size is using less of the lens image circle?

Thanks,

Fred R
Yeah that makes a difference actually. What makes you think that there is no difference.

kevingeller89
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Re: Camera Sensor Size

Post by kevingeller89 » Fri Nov 20, 2015 6:57 am

Semiconductor image sensors can suffer from shading effects at large apertures and at the periphery of the image field, due to the geometry of the light cone projected from the exit pupil of the lens to a point, or pixel, on the sensor surface. The effects are discussed in detail by Catrysse and Wandell .[13] In the context of this discussion the most important result from the above is that to ensure a full transfer of light energy between two coupled optical systems such as the lens' exit pupil to a pixel's photoreceptor the geometrical extent (also known as etendue or light throughput) of the objective lens / pixel system must be smaller than or equal to the geometrical extent of the microlens / photoreceptor system. The geometrical extent of the objective lens / pixel system is given by

G_\mathrm{objective} \simeq \frac{w_\mathrm{pixel}}{2{(f/\#)}_\mathrm{objective}} ,

where wpixel is the width of the pixel and (f/#)objective is the f-number of the objective lens. The geometrical extent of the microlens / photoreceptor system is given by

G_\mathrm{pixel} \simeq \frac{w_\mathrm{photoreceptor}}{2{(f/\#)}_\mathrm{microlens}} ,

where wphotoreceptor is the width of the photoreceptor and (f/#)microlens is the f-number of the microlens.

So to avoid shading,

G_\mathrm{pixel} \ge G_\mathrm{objective}, therefore \frac{w_\mathrm{photoreceptor}}{{(f/\#)}_\mathrm{microlens}} \ge \frac{w_\mathrm{pixel}}{{(f/\#)}_\mathrm{objective}}

If wphotoreceptor / wpixel = ff, the linear fill factor of the lens, then the condition becomes

{(f/\#)}_\mathrm{microlens} \le {(f/\#)}_\mathrm{objective} \times \mathit{ff}

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