Sunday 25 January 2015

Why don't my Canon EOS 600D vs 5D Mark II comparisons meet my expectations?


I had a Canon EOS 600D for 6 years but switched now to a Canon EOS 5D Mark II because I faced the limit of my camera. I do a lot of HDR photography and felt kind of limited after all these years.


I got a really good price for a used Canon EOS 5D Mark II, and I tried it out a couple of times. The more and more I dive into the camera and it's settings I am pretty happy but the image quality is not really much better. Yes, the comparison is not fair, because the 5D Mark has a bigger FOV and therefore I had to scale the image down a little bit, still wondering if you have some tips.


Both pictures were shot with a Canon EOS 50mm, f1.8 and the following settings:


ISO 400, f1.8 and ISO 160 (left) and 125 (right). Is it just me or why did I expect a better quality? Thanks a lot for any input!



enter image description here


enter image description here



Answer



You expected it to be better because people tend to think, bigger = better. People talk about how great full frame is without understanding what is really different, and your expectations are too great.


Sensitivity and Noise


Full-frame sensors have larger sensels than crop sensors that produce the same number of megapixels. For sensors of the same generation, full-frame sensors are expected to have an advantage in ISO sensitivity and noise. However:




  • The advantage is reduced on full-frame sensors that use smaller sensels to produce more megapixels.





  • The advantage applies primarily to high-ISO. Noise is minimized at low-ISO, such as those you used to take your test shots.




  • Sensible lens choices, with faster apertures, reduce the need to push ISO.




  • Newer technologies increase light sensitivity and reduce noise. However, Canon tends to develop technologies slower than molasses, and the EOS 5D mk2 was current throughout the 600D life-cycle. (This is why Sony has a 5-year head start on full-frame mirrorless.)





To see the noise difference between crop and full-frame, you need to take multiple ISO-matched images throughout the ISO range. View them at 100% without resizing. You should see noise become unacceptable at lower ISO settings on the crop sensor vs the full frame.


The "Full-Frame" Look


What your test images demonstrate is, when taking photographs from the same position, with the same lens, with the same settings, everything is the same between crop sensor and full frame, except field of view. Changing sensor size just changes the portion of the (exact same) imaging circle that is recorded.


What creates the "full frame look" is what people do to compensate for the different field of view. To fill the frame with the subject on a full-frame sensor, the camera has to be closer or the lens has to have a longer focal length. The difference can be reduced on crop sensors by using faster apertures, when available.


No comments:

Post a Comment

Why is the front element of a telephoto lens larger than a wide angle lens?

A wide angle lens has a wide angle of view, therefore it would make sense that the front of the lens would also be wide. A telephoto lens ha...