Why are my DREBEL images NOT SHARP

[rammy]

Hi all,

I've been using my DREBEL for sometime now and don't seem to get any pin sharp images. By pin sharp, I mean at any focal length with good DOF. I am particularly interested in landscapes and panoramics which never come out pin sharp.

I have taken varied shots over the year, portraits, landscapes etc and they never seem to come out sharp. I have used tripods etc also. I use Manual setting on camera all the time. Even if I post-sharpen in PS, I cannot get good "crispness" because the original is not too sharp in first place.

Is it to do with with lens kit (18-55) standard lens? I do not have the Firmware so do not use MLU. It is even worse on 75-200 lens.

Has anyone else experienced this?

[tommykjensen]

It could be the lens You use but it can also be the settings, aperture, shutterspeed etc. So You should probably post a few photos with exif data.

My personal experience with the kit lens was not good. When I had 300D the few shots I took with the kit lens was horrible. I have not shot a single photo with the kitlens on my 20D ! (Could not get a body only when I bought the 20D ;-) )

[rammy]

Here is an example:

Shot using a 75-200mm lens. I tried to get the leaves on the table pin-sharp:

http://www.crystalsymphony.plus.com/Temp/IMG_2358_75-300.jpg

[rammy]

Also this one shot on 18-55 lens has ISO set to 1600. I tried to get front to back sharpness. Was this because of ISO?

The front posts and buildings at the back are not sharp. Is this a Hyperfocal thing?

http://www.crystalsymphony.plus.com/Temp/IMG_0218_55mm.jpg

[tommykjensen]

The first shot: Did You use a tripod? With a shuttertime of 1 sec and aperture 5.6 You really need very steady hands to get it pinsharp.

[rammy]

First shot: Used a tripod and a remote control to fire the shutter, so did not have to touch the camera. I also shot it 0.5 bracketed and all three images came out the same sharpness. The focal point was the red/orange flower on the table.

Second Shot: Handheld, focused on the ship.

[tommykjensen]

Have You tried sharpening the photos?

I just tried running both through a little sharpening in PS CS and both can get sharper even on the low resolution images. Especially the first one.

[Ajay213]

Which lens is the 75-200? It may not be very sharp at f5.6. I know my 75-300 consumer grade lens is fairly soft wide open (5.6 at 300mm).

On the second picture, basically the same deal but at the other end. At f22 (to get the DOF) you're well past the point of "razor sharp" for the kit lens. I don't know how far you were from the ship, but I'll guestimate it at around 15ft? Plug the numbers into a DOF calculator and you get;
at F22
Near limit of sharpness - 2.1 ft
Far limit of sharpness - infinity
Total DOF - Infinite
DOF in front of subject - 12.9 ft
DOF Behind subject - infinite
Hyperfocal distance - 2.53ft

At F8
Near limit of sharpness - 4.78 ft
Far limit of sharpness - infinity
Total DOF - Infinite
DOF in front of subject - 10.2 ft
DOF Behind subject - infinite
Hyperfocal distance - 7.05 ft

So technically you should have gotten acceptable DOF by shooting F8-F11.

Hop onto Pbase and search on "landscape" and take a look at the EXIF info posted, most big landscapes are done in the F8-F11 range.

DOF calculator - http://www.dofmaster.com/dofjs.html

[rammy]

Hi tommykjensen,

Yes I can get some crispness by using USM in PS but something happens with a landscape image or an image that has contrast between, say a building and sky. The sharpness starts adding a "halo" to the image. For example, this image was sharpened in PS and look at the green halo around the edge of the building. Where did that come from? If I had taken image sharp in first place then I would not have these "edge" problems?

(Image was cropped and zoomed in):
http://www.crystalsymphony.plus.com/Temp/Halo.jpg

Hi Ajay213,

Thanks for the calculator, I used a Hyperfocal chart to focus appropriately. I will try your calculator link. Thanks!

[Hellashot]

It's likely all you need is more sharpening. Images even using default JPG shooting settings need to be sharpened more. USM in Photoshop does wonders.

For the 1st shot, a 1 second exposure could have added motion to the image. The second one, you could have likely gone down to ISO400 instead of 1600. The look fine with proper sharpening.

It'll be a while until digital images do not need sharpening, unless you possibly want to spend a lot of money for one of the professional models.

And that "halo" you're referring to is likely an overexposed part of a bright building catching sunlight. Nothing you can do about that. Plus it is a very small part of the image and not the subject of the image.

[dlhedg]

My opinion in sharpening the pictures is to start with a glass lense other than the one that came on the Rebel. I have a tamron 28-70 f2.8 my pictures have dramatically changed since the purchase of the new lense. This should help and keep your iso low enough to expose the picture but not wanting to cause grain in th photo
thanks
dan h

[blinking8s]

I never shot high iso's with the dreb, I also never ever had a sharpness issue even with the kit lens. Either its user error or the camera...

[kawter2]

Either its user error or the camera...


Wow Im going to have to write that down Will!!!! :)

[Ajay213]

I'm still sticking to my originally theory of shooting with an aperture that isn't known to be sharp. Sure USM is great for fixing problems, but he should be getting a lot sharper pictures out of the camera to start with.

Below is a 100% crop taken with a 20D with "default" settings, from a 75-300 lens (in "macro mode") at 300mm, the lens brand shall remain nameless, but needless to say it was dirt cheap and earned an absolutely horrible rating on Photodo. Also note that the RAW file is a bit clearer as it didn't go through 2 JPEG compression routines.
1.3Sec @ F8 at 100ISO

[Shakey]

It is the kit lens . I have 2 other lens both what would be considered low value budget lens(as is the 18-55EF-s)
A 35-105 f4.5 canon kit lens that came with my film Rebel II circa 1994
A 50mm f1.8 canon (the nifty fifty)
Both of these lenses have out performed the Drebel 18-55 kit lens by far.
My kit lens is used mostly for Wide angle (relative wide angle that is) ;)
Alas I like so many before have found that I need glass. I said when I bought it that I would be content with the kit lens... how wrong and naive I was.

[rammy]

Thanks for the information. I gather that the sharpness is to do with either the Lens Kit that I am using or the DOF used at a certain aperture value.

I will give these shots another go with varying aperture and focal length so I can learn for myself what has been discussed.

Thanks for help.