Equivalent focal lengths - never thought of this before...

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Originally Posted by revi

True and false :)
The image on the crop sensor will be smaller, but so is the sensor. So the image will take up as many pixels on a crop sensor as on a full frame sensor with the same number of pixels.
Otoh, if you use a cropped sensor with more pixels than the full frame you compare with, it's the FF that will show the most pixelation :rolleyes: (if you ever get to a print size where that gets important)

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Thanks Remco,

I am not sure I can agree with this one.

Nikon D300 = 12.3MP Crop sensor / Nikon D700=12.2MP FF. Difference in Image quality between the two? Understand my point – why spend money on a D700 if the D300 can do the job better?
Why would Nikon build a D700 if the D300 can do a better job?

No Remco, I think it is a little more complicated than that.

I cannot for one moment believe, the image captured with a D300 will equal or surpass the quality of an image captured with a FF D700, using exactly the same Nikkor lenses. You will have to proof that to me.

We have to remember we are not only looking at printing images, the cropping in PP can be worse than printing when we start pixel peeping. Do you think the D300 image will render a better crop than the D700 image? :confused:

My head is hurting more than Terri's now. Think I must have a drink while you figure this one out. :eek:

Everything that has been written about how the image is the same size for a given focal length (ignoring the issue of the image circle) is absolutely correct. The central part of the image will be the same across the range, with more image showing up on the larger sensor, albeit at the same size.

What the writers keep forgetting about is that we do not view the output of a digital camera at sensor size, but rather enlarge it for viewing on a computer screen or as a physical print. This means having to look at things from the output view, not the camera view; a crop frame, full-frame and medium format camera will all have the images enlarged to the same size on a specific screen or print size. This additional enlargement is effectively where the crop factor will be noticed and turns from a theoretical issue into something quite real.

So crop factors are really the effect of enlarging the capture by different amounts to match the specific output format

That's why I insisted on comparing equivalent pixel counts:
the crop sensor will be enlarged more, but will end up with the same number of pixels/inch as the full frame.

The difference between crop and full frame is in the size of the photo sites, and this gives an advantage to the full frame sensor:
- better S/N ratio at low light levels (so larger dynamic range and better shadow detail)
- less likely to run into physical limits (diffraction) or problems with lens resolution.

What will NOT happen is that a cropped sensor suffers from more pixelation when increasing the magnification (for the same number of MP)
So yes, a D700 can be expected to give a better image quality than a D300, but not due to the D300 image being pixelated (which is what Andre claimed).

And is the gain in image quality that visible for screen-sized images or prints up to say A3?
(how many here print larger, except Colin Southern?)

(Medium format has usually many more pixels than the smaller sizes, so that makes comparison even more complicated.)

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Originally Posted by revi

(how many here print larger, except Colin Southern?)

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My most second most common print sale has been 24" x 20" for a few years.
My most common print sale is 11" x 14" / 11" x 16" or thereabouts.

WW