Image sharpness - full versus smaller sensors

I have been shooting for a few weeks with my new Canon 450D and I do like its light weight and relatively uncomplicated menus etc for shooting in the field. It appears to me that the sharpness and color accuracy are OK, but I kind of think I should be getting a bit more sharpness and color saturation than I am getting from the combination with my 300 f/4. I know some of the sharpness issues come with poor technique, but I have been really concentrating on that and just taking images in controlled situations and the sharpness still seems less than what some are getting with the same quality of lens. My question is, is the small sensor on the 450D limiting sharpness and color saturation vs what can be achieved from a full sized sensor (e.g. 5D)? I have read a bunch, but want some people who have been out in field with both types of sensors to provide me their opinions on this. I trust you all here at NPN. The proof is in the images posted here on a daily basis. Thanks for your time in helping me out. Ron

Ron - can you post a sample picture that shows us what you're seeing? If you're looking at the RAW images, all RAW images require post-processing. They're intentionally flat, unsaturated and not sharpened. This provides the greatest flexibility in post-processing.

If you're looking at .jpgs, there are likely settings in your camera for how the 450D will process the RAW data into a .jpg and those can be adjusted.

Posting a sample will help others provide more detailed feedback.

The antialiasing (low pass) filter that sets in front of the sensor contributes to a lack of sharpness.
See this short tutorial on that effect and why sharpening is almost always needed via postprocessing.

Ron, what kind of tripod and head are you using?

Ron - To more directly address the sensor size issue (and for disclosure, I've never shot full-frame, but know a bit about it) : A full frame sensor with the same number of pixels as your 450D could potentially be sharper than the smaller sensor. However, the difference is irrelevant compared to all the other factors that go into sharpness (good lenses in good working order, good field technique, proper processing whether in camera jpg or raw file). All it should take is a look at some results that others are getting with the Canon Rebel line.

Seeing as how you are definitely using an excellent lens, I feel like the most likely culprit is a lens that's out of spec, camera movement, or not enough sharpening being applied to the file.

A very controlled test of a highly detailed subject in good light with the camera locked down (crisp money taped to a white wall is kind of a standard) might show you what's going on.

Thank you all for your comments. I am new to shooting RAW images and did not realize what that meant as far as post-processing needs. I have not shot a JPG image with the Xsi (i.e., let the camera do the processing) until your comments spurred me to. I have always shot RAW and post processed in PS. It was my thinking that I was having to do more post-processing than I actually should have to do. I have been able to produce some very nice images with post processing. But I have now shot some images and the let the camera do the processing to JPGs and they really do look good. I will continue to shoot in RAW format and do the post processing because I do see now the flexibility it gives a person and that the amount of processing I have had to perform is not out of the ordinary. Thanks for bareing with my poor knowledge. I knew you all would be able to clear this up for me and you have. Happy holidays. Ron

Ron--one thing you can do is to set your camera to save both a raw and jpeg file for each shot. That way you can compare the results side by side in PS or DPP. It will eat up more space on your flash cards but it is a good way to learn. Also, you can customize your in-camera jpeg processing parameters. Once you develop a workflow for your raw processing I think you'll find it less laborious since many repetitive steps can be more or less automated. A good book to review is PhotoShop CS3 for Nature Photographers. There are also a lot of good websites that lay out PS workflows--Larry

Just for your info Ron, I have been shooting with an Xti for over a year. As long as I practice very good technique, 1. Sturdy Tripod and Head a MUST, 2. Mirror lock with time release or remote shutter release 3. Critical manual focus. When all these elements are in play, this camera can and will produce excellent sharp images no question. And this is without mentioning quality glass as being another critical factor in given situations.

Larry and Brad, thanks so much for your input. I am working on my PS work flow and getting it down pretty well. I am going to try the dual capture mode for a bit and see how that goes. Great suggestion. I am going to get a remote release for sure. Many times I will not be able to use one (I am mainly into photographing birds), but I do like to take landscape shots too and I know it is a must for that. Happy holidays to all.

Also for a nice RAW workflow look into some software like Lightroom or aperture or Capture1
it will greatly enhance and ease your workflow !

Wim

Another thing to look at is focusing. I believe your 450D has live view, so it's easier to do comparisons of auto focus with manual focus. I say this because my 40D has slight focusing issues with my 70-200L, one of my sharpest lenses. I now use live view a lot and have been able to overcome the slight lack of sharpness I was seeing using my 70-200.
Happy holidays!

I've been thinking about this very subject recently after spending two weeks in Florida shooting with a D300 alongside my D3. I'm going to do a test in the next few days with a test shot from both cameras, upsizing a shot from my D3 in crop mode back to the resolution of the D300 to see what the differences in resolution are...