sportyman140 Loc: Juliette, GA

It usually means that when you lock mirror up you are reducing the vibrations in camera shake for help in a crisper clear picture.

Shaka Loc: Brisbane, Australia

Hi Millismote, I have a Canon 100-400 lens, which I use on a Canon 60D and I've been experiencing the same problems. Thought that it was due to most of my pics being hand held. Today, I used my tripod exclusively and forgot to switch the IS off. The results were embarrassing! As soon as I downloaded the pics onto my computer I realised my mistake, which has been confirmed here. Switch the IS off when using a tripod! I'll also take into account any other advice here. Thank you for brining this topic up.

Millismote Loc: Massachusetts

Festini, I took this picture on the tripod of some trees across the pond. IS was turned off and the auto focus was on spot and on the trees (distance about 300 ft) in the foreground. The settings are part of the download picture. The soft focus is typical of my pictures when viewed at full size. I was hoping for something sharper then this.

Mr. B Loc: eastern Connecticut

Festina Lente is spot-on in his remarks. I, too, bought one that was soft. I do a full autofocus test and resolution test on all my purchased lenses. B and H Photo took the lens back and sent me another which was tack sharp. It pays to test your lenses if you want a definitive answer as to how sharp they are or how well they focus at the target distance.
I have attempted to attach two aids for you to use. I don't know if this will work but we'll give it a go. Hope it helps.
Mr. B

Autofocus chart


Resolution target

Grizzly Loc: USA

If photos are unsharp, I support the writers who suggest IS be turned off while on a tripod, and make sure the lens is calibrated to the Canon 50D. Stopping down to f/11-16 may help.

Bridges Loc: Memphis, Charleston SC, now Nazareth PA

In that range don't overlook the Tokina 80-400. I played around with this lens at a photo show last year and found it to be extremely sharp. Even when mounted with a 1.4 Kenko Pro extender, it was still sharp. The downside to this lens is that it is not VR/IS, but then again, who shoots this size lens hand-held anyway? It focuses much faster than the Nikon 80-400 with equal to or better sharpness.

jerryc41 Loc: Catskill Mts of NY

Do you have a link for the Bob Atkins chart? I couldn't find it online.

jerryc41 Loc: Catskill Mts of NY

Here are some links for checking focusing.

Checking Autofocus on a DSLR
http://mansurovs.com/how-to-quickly-test-your-dslr-for-autofocus-issues
http://mansurovs.com/wp-content/uploads/2012/07/Siemens-Star-Focus-Chart.pdf
http://mansurovs.com/wp-content/uploads/2012/07/Focus-Test-Chart.pdf
http://regex.info/blog/photo-tech/focus-chart

Mr. B Loc: eastern Connecticut

Here is the website. Click the link below the illustrated chart to access and download the chart..
http://www.bobatkins.com/photography/technical/lens_sharpness.html

jerryc41 Loc: Catskill Mts of NY

Thanks. I added that to my Bookmarks.

Mr. B Loc: eastern Connecticut

You're welcome!

gessman Loc: Colorado

You've got several things going on here that, you could/should look at, all related to the idea that you should read your manual and become more familiar with your camera, rather than asking here for answers that will likely only confuse you because so many will answer who have no clue as to what is going on in your particular case, especially if you insist on reserving the right to demand that they answer only the questions you ask and then to do so in a particular way. If, when you study about your camera, you don't understand something, you should use google, youtube, Adorama tv, etc., to find the answers you don't know before you try to determine what is and isn't good based on some across the pond shot that is not near specific enough. I'm not being sarcastic or personally critical - just telling it like it is.

First, from your exif data it shows that you have Peripheral Illumination disabled. That feature allows the camera to know what lens you have on it and allows the camera to adjust to the particular idiosyncrasies of about 25 of Canon's most popular lens one of which is probably the one you're testing out. Second, you have your picture type set to 'Faithful' which is basically "dumbing down your camera" since all the settings are flat, disallowing any in-camera processing to enhance your images, brightness, color saturation, sharpening, etc... Third, your camera DOES allow micro-adjustment which you can do with that lens if the previous suggestion doesn't help. Here's how: http://grfxguru.wordpress.com/2008/10/23/my-canon-50d-opinion-has-improved-micro-adjustments-to-focus-rock/

Finally, if you had googled 'focus problems with Canon 50d' you would see from the 775,000 hits that google returns that the complaints never end but a few of the users have been on the ball, studied, their manual or otherwise, and figured out that you CAN fix it yourself with the micro-adjustment feature.

Some time in all of this I would suggest you go to the following link and read what is there - it's short and sweet. http://www.luminous-landscape.com/reviews/lenses/forgotten-400.shtml

CAM1017 Loc: Chiloquin, Oregon

I shoot with a 60D and this lens. I use it mainly for inflight bird photography. Normally I hand hold using ISO's of 400 to 800 at F8 to 11 and try for shutter speeds of 1/2000 to 1/2500. Cropping and post processing is done in Aperture 3. For me me this is a very acceptable combinations.

Canikon Guy Loc: Baltimore, MD

I have the same camera and lens.
50D with the 100-400mm "L" with IS. I use this set up for planes.
Here is an example of the lens shot a 400mm:
http://www.flickr.com/photos/olympic707/8023845637/in/set-72157627626412733/
Click on the Canon EOS 50D to see the EXIF.
I shoot hand held with the IS on.

Try this:
1- Like others said, turn IS off when using a tripod.
2- Set the proper AUTO FOCUS.
a- For stills use ONE SHOT auto focus or if something will move use AI FOCUS (automatic). Don't use AI SERVO, that is for moving objects.
b- Try different Auto Focus points. CENTER sometimes works better that AUTO.
3- Use Remote Sutter Switch. Canon P/N RS-80N3.
4- Use APERTURE PRIORITY. Set it 7 or smaller. You might have to experiment on what works best.
5- Shoot RAW.
6- Use sharpening / USM at post processing it makes a BIG difference.

The 100-400mm "L" is a very good lens. No Sigma or Tamron for me.

With a rental lens, who knows how it's been handled.

jeep_daddy Loc: Prescott AZ

I have this lens too. Canikon Guy says it all. You need to experiment with a new lens to find what works and what doesn't. Every time I purchase a new lens or body, it usually takes a couple of weeks to test and see what works - especially the 100-400. It stands to reason that a prime lens will be sharper than a zoom so don't let that other experiment bum you out. Zooms have advantages over primes and vise verse.

One thing you need to listen to is the last thing that Canikon Guy said. "With a rental lens, who knows how it's been handled"

I checked your image and it should be sharper than that. When I take landscape shots I usually shoot between f8/f22. I also use one shot focus and not AI Servo. I'll usually use a remote shutter or a 2-10 second delay. If the subject is really distant, I'll use mirror lockup. The 50D doesn't have video capability (I don't think it does anyway) so it may not have 'Live View' - but if it does, try Live View and use the LCD zoom and manual focus. On a tripod this is a great feature for landscape and moon shots. Also, if you are shooting jpg, check your picture styles and see if the sharpening has been altered. I've seen what happens to a jpg if the sharpness in a picture style is all the way left. (or turned down) Very soft! If you're not shooting in raw, you really should be as Canikon Guy said.