About two months ago I upgraded from a Canon XT to the 7D. The thing I notice the most is while the XT would deliver a smooth creamy bokeh, the bokeh on the 7D comes out grainy and gritty looking even at ISO 100. I'm not sure if this is considered noise because it shows up at even the lower ISO settings and my subject will be nice and clear, void of any grainy or gritty texture that the BG will have.
I have noticed this bokeh texture with other photographs on this website as well and not just with the 7D but with other makes and models, even with the higher end cameras. Any explanation?
FYI, the in camera long exposure NR is off (though my images aren't long exposre) and the high ISO NR is set to standard (not that it matters because I'm at ISO 100). I get this with all my lens. I'll shoot RAW and try to clean this up with the NR in Canon's DPP software. It will smooth out this grit but also makes my subject soft and unsharp. I've done side by side comparisons with the 7D and the XT with a Canon 100mm macro lense attached. I took the same image with both cameras set at ISO 100, 400, 800 and 1600. The 7D obviously controlled the noise better in this situation as the ISO increased yet at ISO 100 and even 400 the BG was grainier on the 7D, though the subject itself looked great.
Thanks for any info you might have with this matter. It's not terrible by any means but it's noticeable to me and it troubling for me to wonder if I'm better off forfeit ALL the great options the 7D offers if overall photo quality is better with an obsolete camera like the XT.
John - First things first - any noise you're seeing will be the same, OOF area or not. Noise is a lot more based on the exposure level/brightness, so I'm guessing that areas where you see less noise are also brighter. OOF areas also seem to have more noise sometimes because they are so smooth, making noise more apparent.
Now as for the 7D/XT question : How are you comparing the images from the XT and 7D? Are you looking at both at 100% on screen? If so, what you're seeing sounds normal. The 7D has 18 MPixels, a far cry from the 8 MPixels in the XT. And while the technology has gotten better, mitigating the effect somewhat, smaller pixels still generally means more noise at a pixel level. However, with 18 MP, you won't be blowing up your images nearly as much as with the XT, and all that extra resolution should more than make up for the noise.
Here's something you could try : Do the same test you did before at all those ISO's, but this time re--sample the 7D images down to match the 8 MP of the XT. Then take a look at both on equal footing. I'm actually curious about exactly what you'll see, but I suspect you'll like the 7D a lot more.
David: Thanks for your input. To answer your question about viewing at 100%: I can see the grainy BG with just the photo on my computer screen before any enlargement. I can view both the 7D and the XT at the same time in a side by side comparison and then sync them together and enlarge them to different levels to see the effects that way as well.
You mentioned to "resample the 7D down to the 8MP of the XT." I'm not sure what you mean here, I can adjust my image quality in the camera to medium/fine or medium/normal to get a pixel size of 8MP, is this what you mean? If so I'll give it a try.
Resampling is to resize the image to the same pixel size as the XT.
Open up an XT image. Look at the dimensions of the image measured in pixels. Next, open up a 7D images. Resize the image to the same pixel dimensions as those from the XT camera. Now compare the two.
Don't let the camera resize the image, even if it will produce a file with the same pixel dimensions. You want to be able to evaluate the images based on your editting workflow and the camera isn't part of this - it is part of the capture workflow.
John - I'm a little surprised you can see the effects at equivalent sizes on screen John, but that's also letting the software potentially do odd things to show them at that size., Resizing and comparing both images at 8 MP and Dan explained will be more certain. Also make sure you get the same exposure with your comparison shots (same histogram - which might be slightly different than using the same exposure settings). Otherwise you could potentially also be seeing differences in exposure, rather than just comparing the noise.
Discussion
4 repliesI have noticed this bokeh texture with other photographs on this website as well and not just with the 7D but with other makes and models, even with the higher end cameras. Any explanation?
FYI, the in camera long exposure NR is off (though my images aren't long exposre) and the high ISO NR is set to standard (not that it matters because I'm at ISO 100). I get this with all my lens. I'll shoot RAW and try to clean this up with the NR in Canon's DPP software. It will smooth out this grit but also makes my subject soft and unsharp. I've done side by side comparisons with the 7D and the XT with a Canon 100mm macro lense attached. I took the same image with both cameras set at ISO 100, 400, 800 and 1600. The 7D obviously controlled the noise better in this situation as the ISO increased yet at ISO 100 and even 400 the BG was grainier on the 7D, though the subject itself looked great.
Thanks for any info you might have with this matter. It's not terrible by any means but it's noticeable to me and it troubling for me to wonder if I'm better off forfeit ALL the great options the 7D offers if overall photo quality is better with an obsolete camera like the XT.
Now as for the 7D/XT question : How are you comparing the images from the XT and 7D? Are you looking at both at 100% on screen? If so, what you're seeing sounds normal. The 7D has 18 MPixels, a far cry from the 8 MPixels in the XT. And while the technology has gotten better, mitigating the effect somewhat, smaller pixels still generally means more noise at a pixel level. However, with 18 MP, you won't be blowing up your images nearly as much as with the XT, and all that extra resolution should more than make up for the noise.
Here's something you could try : Do the same test you did before at all those ISO's, but this time re--sample the 7D images down to match the 8 MP of the XT. Then take a look at both on equal footing. I'm actually curious about exactly what you'll see, but I suspect you'll like the 7D a lot more.
You mentioned to "resample the 7D down to the 8MP of the XT." I'm not sure what you mean here, I can adjust my image quality in the camera to medium/fine or medium/normal to get a pixel size of 8MP, is this what you mean? If so I'll give it a try.
Again, thanks for your help.
Open up an XT image. Look at the dimensions of the image measured in pixels. Next, open up a 7D images. Resize the image to the same pixel dimensions as those from the XT camera. Now compare the two.
Don't let the camera resize the image, even if it will produce a file with the same pixel dimensions. You want to be able to evaluate the images based on your editting workflow and the camera isn't part of this - it is part of the capture workflow.