My Lens Does Suck ... Scientific Test

chuckinsocal

OK ... not THAT scientific, but ...

Here are two photos with originals enabled (the photos were cropped down to just the box) ... the printing on the box is razor sharp. I shot at Aperture Priority at f10 thinking that would give me a pretty sharp image. One image is at 50 mm and the other is at 135 mm. Image Sharpness is set at +2. I shot with a tri pod and a remote trigger to eliminate camera shake.

The lines and printing are not nearly as sharp as I'd expect. Maybe it's the best I can expect with this lens? Maybe my expectations are too high? Maybe it's an auto focus issue? Maybe it's a defective lens issue? Maybe I"m missing some camera settings? I really have no idea but I'm getting closer to just not liking this lens.

I understand that I'm not gonna get the results I would from a far more expensive pro level lens, but I'm thinking it should be better that this.

Any input would be greatly appreciated.

Thanks.

pyry

chuckinsocal wrote:

OK ... not THAT scientific, but ...

Here are two photos with originals enabled ... the printing on the box is razor sharp. I shot at Aperture Priority at f10 thinking that would give me a pretty sharp image. One image is at 50 mm and the other is at 135 mm. Image Sharpness is set at +2. I shot with a tri pod and a remote trigger to eliminate camera shake.

The lines and printing are not nearly as sharp as I'd expect. Maybe it's the best I can expect with this lens? Maybe my expectations are too high? Maybe it's an auto focus issue? Maybe it's a defective lens issue? Maybe I"m missing some camera settings? I really have no idea but I'm getting closer to just not liking this lens.

I understand that I'm not gonna get the results I would from a far more expensive pro level lens, but I'm thinking it should be better that this.

Any input would be greatly appreciated.

Thanks.

Have a look at photozone's review here and the sample images and compare your results to theirs. The lens seems to peak at f/5.6 - 8.

Check the sizes of your originals in that gallery, the 50mm image seems too small. The 135mm seems more-less acceptable to me. Note that you are never going to get perfect pixel to pixel contrast because the sensor has a bayer mask, and de-bayering involves interpolating.

chuckinsocal

Hi Pyry and thanks for the quick response.

The images in the gallery were cropped down to the box so they may not be scaled correctly.

It appears that the images in the review are about the same as my images so I may have made a bad lens choice. It has an awesome range for walk around stuff but I guess I have to give up some clarity and sharpness in trade. I thought the images I saw in other reviews were sharper but maybe I was just seeing what I wanted to see.

Bayer Mask? Is that like aspirin on halloween ? Seriously, what is a bayer mask. Can the effects of it be mitigated in any way? Does the interpolating occur in the camera?

Maybe I'll try some RAW shots later.

ziggy53

Another potential issue is "Minimum Focus Distance" (MFD). I always do critical focus tests at twice MFD and then close to infinity. When you are at or approaching MFD that is usually not the best that the lens can deliver. MFD can also vary by focal length.

In the 135mm test the word "Perma" and the "registered" mark do seem to be in sharp focus and they are close to the center of the image which is where best sharpness also appears.

You could also change the black-point to the printed area and see an improvement in contrast which would make the lettering appear sharper.

The 50mm test does look soft but lenses of this range tend not to do as well throughout the entire range and will have regions of softness. Again, resetting the black-point to the lettering could improve the appearance somewhat.

For best performance it is still best to choose zooms with ratios of 2 or 3 and constant aperture. This lens has a pretty wide range and ultimately quality is going to be somewhat compromised.

I generally do shoot several images to check for variability and consistancy of autofocus.

Another copy of the lens might be slightly better or slightly worse. Such is the nature of consumer zooms.

pyry

chuckinsocal wrote:

Hi Pyry and thanks for the quick response.

The images in the gallery were cropped down to the box so they may not be scaled correctly.

Ah, I see. Then the 50mm isn't really that bad either.

chuckinsocal wrote:

Bayer Mask? Is that like aspirin on halloween ? Seriously, what is a bayer mask. Can the effects of it be mitigated in any way? Does the interpolating occur in the camera?

Maybe I'll try some RAW shots later.

The bayer mask isn't aspririn ( ), it's the way the sensor handles colour. There are red, green and blue filters over the individual elements of the sensor array and when it comes time to make the exposure into an image, the camera looks at a few adjacent elements together and decides on the colour of the final pixel. This leads to some lack of final sharpness, simply because one pixel on the sensor doesn't directly see all three colours.

You can however take the process of de-bayering the picture out of camera and into a RAW converter on your computer - those tend to do a better job at it than in-camera jpg does and gives much more control over several other things to boot. Give it a shot.

jonh68

Your results are usually why photogs skip the 18-135 and get the 18-200 VR for a general all-in-one lens or get the 18-55 Vr and 50-200 VR. VR helps a lot in low light situations for stationary objects going hand-held.

However, you should get almost as sharp images as pro-glass using a tri-pod in good light. You could have a bad copy.

Brascole

chuckinsocal wrote:

OK ... not THAT scientific, but ...

Here are two photos with originals enabled (the photos were cropped down to just the box) ... the printing on the box is razor sharp. I shot at Aperture Priority at f10 thinking that would give me a pretty sharp image. One image is at 50 mm and the other is at 135 mm. Image Sharpness is set at +2. I shot with a tri pod and a remote trigger to eliminate camera shake.

The lines and printing are not nearly as sharp as I'd expect. Maybe it's the best I can expect with this lens? Maybe my expectations are too high? Maybe it's an auto focus issue? Maybe it's a defective lens issue? Maybe I"m missing some camera settings? I really have no idea but I'm getting closer to just not liking this lens.

I understand that I'm not gonna get the results I would from a far more expensive pro level lens, but I'm thinking it should be better that this.

Any input would be greatly appreciated.

Thanks.

OK we get it your lens freakin sucks. It would be nice to other posters for you to keep you topic in one thread because your knocing topics off the first page

chuckinsocal

Thanks Ziggy and everyone else. Setting the white and black points did clear it up substantially. I guess I was expecting better results straight out of the camera. And, I haven't tried RAW yet. I'll keep shooting, experimenting, and pp'ing and chalk it up to a possibly bad choice of lenses for my first dslr and move on. Maybe keep my eye out for a sharper lens for the future.

I'll quit whining now. Thanks again to all :gone .