ISO on FF vs. Crop

I've read that the ISO on a FF out performs that of a crop. Is this really true, and why?

I am pretty disappointed with the ISO performance with my XS, and am looking to upgrade. Considering the T2i, but the 7D or 5Dc might be affordable for me (I think they are roughly the same cost, 7D maybe a bit more). The 5DmII is most likely definitely out of my range since if I go with FF I will have to replace my kit lens.

Any insight on the comparison of ISO performance on these guys? Particularly why ISO is better of FF if this is true.

Depends which generations of which you compare. The 5Dc is better at lower ISOs than the 7D (only if you pixel peep though), but they go even at 3200 and the 7D keeps going beyond that. The 5DII is about 1 stop better than the 7D.

But as a general rule, you are basically correct.

Here is my own review of high ISO on the 7D vs 5DII.
https://photography-on-the.net …196&highlight=m​ini-review

^^ Thanks, useful comparison. Could you explain the technical use of the term banding here:

Also is the result of high ISO performance simply generational, or is there something about FF that produces less noise at high ISO?

The reason why is because the area of the sensor is larger on the FF cameras, so each photosite/pixel can be larger and collect more light. More light means a better signal to noise ratio.

^^ that doesn't make sense, because then older generations with lower MP should perform better.

mjHession wrote in post #11020314
^^ Thanks, useful comparison. Could you explain the technical use of the term banding here:

Also is the result of high ISO performance simply generational, or is there something about FF that produces less noise at high ISO?

Banding is noise, in a pattern on the image. It's hard to get rid of. You can see it in this post https://photography-on-the.net …ighlight=high+i​so+banding

mjHession wrote in post #11020327
^^ that doesn't make sense, because then older generations with lower MP should perform better.

Well the technology advances as well. Sensor technology, and in camera noise reduction.

Many older cameras have less noise at the magnification. That was one of the complaints of the 50D when it came out. The 40D has less noise per pixel. The 50D has 50% more pixels though, so overall the picture has the same or less noise than the 40D.

itzcryptic wrote in post #11020337
Well the technology advances as well. Sensor technology, and in camera noise reduction.

Many older cameras have less noise at the magnification. That was one of the complaints of the 50D when it came out. The 40D has less noise per pixel. The 50D has 50% more pixels though, so overall the picture has the same or less noise than the 40D.

do you mean more noise? If so this makes sense. Edit: If not, I'm missing something.

For two cameras of similar technology (similar time of release) a FF camera generally is about 1 stop cleaner.

So the original 5D was about as clean at ISO1600 as a camera like the 20D / 30D at ISO800.

The 5D Mark II is a lot cleaner than the 5D because of advances in sensor design (gapless microlenses for the most part) and better A/D conversion capabilities.

The 7D has benefitted from the same advances as the 5D2, so it is now probably as clean or cleaner than the old 5D. The 5D2 is still a stop better than 7D.

I would replace your kit lens regardless of what you do. I would replace that before buying a new body. If it comes down to either opening up your aperture or raising your ISO one stop, the wider aperture is going to provide better images every day of the week.

^^I don't use my kit lens in low light, usually just the 50 1.8. or sometimes the 100-300 5.6. and the 300 2.8 is way outside my price range.

itzcryptic wrote in post #11020318
The reason why is because the area of the sensor is larger on the FF cameras, so each photosite/pixel can be larger and collect more light. More light means a better signal to noise ratio.

True. And if you compare like for like in terms of technological development, the difference is a bit over one stop. This is just as you would expect, as full frame is a bit over twice the area of crop format - 2.56x larger actually, 1.6x1.6=2.56.

The effective difference is a bit more than that, becuase despite 'gap-less' microlenses they are not actually gapless and the gaps on crop sensors take up relatively more sensor area.

The other big advanatge of full frame is sharpness, regardless of pixel count (which is a bit of a red herring TBH). There are two aspects to sharpness - resolution and contrast. Those are the two axes of an MTF graph and the fact of physics is that as resolution goes up, so contrast goes down, and it is actually contrast that makes the biggest contribution to the visual impression of sharpness.

Since full frame asks a lot less of the lens in order to deliver the same ultimate output resolution, the full frame image will always have higher contrast and more pop.

mjHession wrote in post #11020354
do you mean more noise? If so this makes sense. Edit: If not, I'm missing something.

No, per pixel, it has less noise. When you zoom in to 100% on a 40D file vs a 50D file, you will see more noise in the 50D file. Again, that is one reason why the 50D was criticized so badly when it came out. Of course, when you look at pictures of the same size, the 50D will look as good or better because when downsizing the 15MP image to 10MP you usually lose the random noisy pixel.

^^ okay, I get what your saying. The 50D has more noise per pixel despite being a generation better technology because of the denser sensor (less space between pixels)?

If this is right I think I got it. Thanks for your patience and clarification.

Take it from a 5Dc user, you should NOT shoot 1600 on this camera :P..
Unless you overexposure alot, your shots will be horrible..

Trying to shoot weddings inside a church at ISO 1600 without flash is horrid on 5Dc ^^.. I got a 7D now as a companion and can now shoot ISO 3200 - 6400 without starting to cry.