Cropping or Zooming?

Do you lose more image quality croping a picture or using a zoom lens. For example: 70-200L f/2.8 and the 135L f/2 prime. The picture you want is at 200mm but you have the 135mm and would need to crop 68% of the picture. On a 6.3mp you lose about 2mp. For a 10mp you lose about 3+mp.

So what I am asking do you basically break even with the sharpness of a prime with cropping or do you lose too much?

Scotty O

you will lose more in cropping..zooming should have no effect on a lens you mentioned. thats actual glass changing it. Cropping is altering the photo after its taken and reducing its rez.

Agreed ^^^. The more you fill the frame with the subject in the first place, the more resolution you have to work with. Once you start cropping, that res. goes down and IQ suffers.

Seems odd, but on my 5D, with my 70-200L IS, I notice next to no difference between 135 and 200. Not enough that I wouldn't take the 135 instead in low light to get a faster ap and improved sharpness and color. Then again, I've got almost 13mp effective to crop with, so I can crop extensively and still get an incredibly sharp 8x10 with the 135.

cropping on the computer is same as "digtal zoom" on digicams. Avoid it at all costs if you can. Zoom with your feet or with the lens if you can.

Regarding cropping... in Photoshop (CS2 or Elements), if you resize an image to 100% and just crop out part of that image from the center to keep, what have you really lost from the part that you saved? That part of the image is still 100%.

kwsanders wrote in post #2097889
Regarding cropping... in Photoshop (CS2 or Elements), if you resize an image to 100% and just crop out part of that image from the center to keep, what have you really lost from the part that you saved? That part of the image is still 100%.

What you lose is the ability to print it as large as you could have if the desired portion of the subject filled the frame (as much as practical) in the first place.

unless you meant cropping it and then interpolating it to the aprox size image that the longer focal length would render? In which case i would say you could get better results using the better lens, however it would have to depend what lens, what interpolation method and what subject matter, aswell as a host of other factors, but it is conceivible.