Hey /p/
I have a sort of photo theory question for you fine folks.
Now I know that focal length and distance can affect the look of a photo. Taking photo X, then taking photo Y twice as far away but zoomed in 2 times will show different behavior between subject and background.
But I'm wondering if crop conversion make a difference at all. I have a full frame camera and an APS-C camera, so 1.6x conversion. If I took a prime lens, let's say 50mm, and
took one photo with the APS-Camera, so 80mm equiv shot, then took a shot at the same spot with a full frame camera, but then crop it so it's zoomed to 1.6x, would the photos look different, or would they look the same? Maybe the focal lengths described are too short to make a considerable difference, but it's just something I've been wondering. If I wanted to achieve the most shallow depth of field I can, I'm wondering if popping the lens on a crop camera and increasing the effective focal length would make a difference between subject/background, or if the only difference is maybe the image resolution since you'd be cutting down the full frame picture to get the same framing.
Other than different depths of field the images will look exactly the same. The only thing that affects the compression between foreground/background is how far away you are from the subject, as long as you are in the same position and use the same field of view it doesn't matter what format and focal length you use.
So would the depth of field of a 50mm on a crop sensor be shallower than a 50mm on a full frame then digitally cropped?
>>2774711
Everything you need to know is in this shot.
left is full frame, right is aps-c.
not this shit again
Basically, it makes virtually no difference.
>>2774706
This.
But don't forget to multiply the aperture by the crop factor as well.
>>2774735
>900px.jpg
yeaaah boyeee
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I also have a photo theory question. It's not worth making a thread so I'll just post it here.
In one of Tony Northrup's videos on ISO and crop factor, he states that the noise levels is based on crop factor ^2. This means the noise levels of a m43 camera at ISO 200 is the same as a FF camera at 800 ISO (200 * 2 * 2). Can someone explain why he's wrong or right?
this is plain physics: an 80mm lens image cannot look a 50mm image or any other. It will always look like a 80mm lens.
the only thing the cropped sensor will be able to do is to crop out part of the image.
That way, a 80mm lens, for instance, will never be able to produce a 50mm lens distortion. Its physically impossible.
keep in mind, a different sensor will always result in a different image for other reasons (sensitivity to light is one of them, the fact that you have cropped edges is another one), but the lens part will remain unchanged.
>>2774774
I don't know if those numbers are right, but if the sensors have the same resolution and are built with the same technology, the smaller sensor will have more noise because each pixel sensor is physically smaller. That means it has less opportunity to catch photons in the time the shutter is open.
That's why cameras like the sony a7 (r or s, I can't remember) has better low light performance than its brothers. They halved the pixel count so each pixel can be twice as big and catch twice as much light.
>>2774774
I`m no expert at this but a smaller sensor will produce more noise than a larger one. Thats pretty much a rule.
I honestly don't thing you can actually make a usable correlation the way you`re suggesting. All sensors, even if you`re considering only FF, behave differently.
There is such a thing as pixel size and sensitivity. Quantity of pixels. Then you can add build quality. Thats why some FFs will be not as good as others, given the same situation.
Some FF sensors are better than other on low light, other have a better dynamic range and so forth.
But maybe I just don't know enough about cameras.
>>2774795
thats right.
even keeping the same sensor size, only the fact that one sensor is 12MP and the other is 23MP will make a difference. The 12MP will need to have larger pixel sensors than the 23MP, given that the size of the entire sensor remains about the same.
that will not only change sensitivity to light but also dynamic range among other things.
>>2774774
This is sort of right as the other folks have explained. There's a lot of tech that goes into making sensors and some companies are making better sensors than others.
Just as an example, there are also things like micro lens arrays. The pixels on a sensor don't take up the whole area of the sensor. They actually take up maybe 60%, so some companies make tiny lenses one for each pixel, and channel light into each pixel. This increases the performance of the sensor without changing the sensor size.
>>2774801
>noise
>DR
Although what you said is all true its not relevant to the OP.
He just wants something based purely on telephoto compression not photo sites.
>or maybe its the wrong thread
>>2774795
>>2774801
>>2774806
>>2774839
Thanks guys. It seems like the consensus is that assuming the same amount of MP and everything else equal, FF's pixels are larger and therefore contain more light per pixel, meaning less noise.
But what about downscaling? I understand that the A7S series is great at low light because it has such a low megapixel count, but could you get similar performance from a A7R series but scale it down to 12 MP? Or even scaling them both down to 2MP for web viewing?
>>2775067
Down scaling in what way? If I'm correct the physical size of the pixels will remain the same.
One benefit of down scaling images though is that noise becomes less apparent at lower resolutions.
The D800 is often knocked for having poor low light performance but if you down size the images to reasonable resolutions I find it has nearly identical low light performance to other FF bodies.
>>2774747
The aperture multiplication thing is only for figuring out what your bokeh will look like. As far as amount of light let in to the lens f8 is f8 no matter the sensor size.
>>2774795
>Phillips 6MP CCD FF ftw
