thomas-b wrote in post #19212488
I don't have an answer for whether the Raynox will fit with your twin flash. I just wanted to mention that the reduction in image quality from using the Raynox filter is negligible. I've been using it for a while now and have been very happy with it. I would not consider it optically degrading.
Gonna necro an old post, and thread, to put out my .02 for what it is worth...
There are two undercurrents in this thread that I want to address:
1) Adding glass to a lens degrades image quality -false. Adding low grade glass will, but you get what you pay for and if the quality of the glass is high the "image degradation" is minimal to nonexistent.
2) Adding extension tubes to a lens does not degrade image quality (the "it is just an air gap" argument) -false. A lens is designed to create a sharp image circle at a fixed distance from the image plane. Increase that distance with tubes and "image quality" can suffer. People think that Canon's MP-E 65mm is less diffraction prone, but in reality it has a floating lens group that corrects the focus as the mag changes. There is a synergistic relationship between diffraction, lens sharpness, and motion and not all detail loss in macro is just due to diffraction alone. I would also argue that the quality of the light that you are shooting with can rob you of more detail than diffraction.
I put "image degradation" and "image quality" in quotes because absolute image sharpness is a false metric that has nothing to do with image quality. No one views images at 100% pixels, takes a crop at that view, and then saves those crops to a device as wallpaper or prints them. Everyone consumes images by looking at them edge to edge. If you cannot get someone interested in the thumbnail view that most sites generate then odds are they will not even click on it to see your photo...