Lens sharpness issue?

I bought a 85mm 1.8 last year based on my great experience renting one. However, for some reason, I can never seem to get the same sharpness out of mine in comparison to the rental lens. I am starting to wonder if something isn't right with my lens.

Here is a comparison. Top photo is with my copy of the 85mm and the bottom is the rental 85mm.

IMAGE LINK: http://s59.photobucket​.com …media/IMG_6927-1.jpg.html

Not every marriage of lens and camera is the same, even same camera and same model lens. That's why nowadays we have MFA. Have you done it?

Should this not be in the Lens sub-forum or possibly the EOS Body one, rather than the Post-Processing one? Much more likely to get ueeful answers in those places. If you really have a problem with either focus, or just generally being a bit soft PP is unlikely to offer you a solution to the problem. If your camera offers MFA I would try that first. I would also do it at your typical actual working distance for that lens, from what I understand of that process that should give optimum results. Unfortunatly my 20D pre-dates MFA so I have no practical experiance of the process to share.

Alan

I would first check your current lens with similar settings (aperture, shutter speed, ISO) as the sharp photos from your rental lens and use live view (or even better manual focus using live view) to test. Try a few times to really make sure focus, shutter speed, ISO, etc. didn't contribure to any lack of sharpness or loss of details. If your lens is problematic in these conditions, possibly a defective copy. If it's good, start narrowing it down to the cause of the issue.

Keep things simple.

Camera on a tripod, fixed well lit subject, manual focus with x10 live view - THAT should give you a nice sharp image.

If it doesn't then it's gonna be a lens issue.

If it does then it's an auto-focus/MFA issue.

In addition to what LeeRatters suggested, run through your aperture range with your test scenes. try a few different scenes with various planar features, or subjects at different depths and curvature to see how the system responds across the entire imaging field.

As pointed out - be very deliberate in your focus. AF should work, so include AF tests as well as MF tests in the same scene.

There is always chance that it is a user issue until you find otherwise.

kirk

LeeRatters wrote in post #16752682
Keep things simple.

Camera on a tripod, fixed well lit subject, manual focus with x10 live view - THAT should give you a nice sharp image.

If it doesn't then it's gonna be a lens issue.

If it does then it's an auto-focus/MFA issue.

If its an MFA issue, then mounting it on a tripod will not prove anything.

Lowner wrote in post #16752929
If its an MFA issue, then mounting it on a tripod will not prove anything.

It will prove the soft image wasn't a result of the camera moving backwards or forwards between obtaining focus and taking the shot.

Lowner wrote in post #16752929
If its an MFA issue, then mounting it on a tripod will not prove anything.

The only way to probe micro-focus adjustment is to eliminate all of the other factors that affect focus. You must fix the working distance, the focal length (in this instance, 85mm prime lens, right?) and the aperture. Then you can use a test scene with careful focus to tease out any effects of your AF system (an angled ruler works well).

There are all sorts of tutorials on the web that lay out how to test for and set MFA. Best to make sure that you are focusing CORRECTLY before you start monkeying with the factory settings.

A simple test would be to set up a test scene with the camera locked down. Place the AF zone on a prominent, well contrasted area of an angled ruler and engage one-shot AF. Engage Live View and do the same with the Live View AF. Finally, use Live View and a loupe to focus manually.

Also - is your eyesight okay? If you focus through the viewfinder, is the focus screen sufficient for your needs? Is the dioptric adjustment set properly?

Remember to turn of IS if your lens has IS. Also, use a remote shutter release or timer to eliminate blur from camera movement.

Eliminate all confounding variables and then compare the three images. Repeat for all apertures, while maintaining standard exposure.

kirk

Sorarse wrote in post #16752953
It will prove the soft image wasn't a result of the camera moving backwards or forwards between obtaining focus and taking the shot.

True.

Sorarse wrote in post #16752953
It will prove the soft image wasn't a result of the camera moving backwards or forwards between obtaining focus and taking the shot.

This, there was a recent thread where a user complained about the same lens with sharpness issues and inconsistent focus. He had several test shots in a "controlled" setup. All of his problems disappeared once he started using the tripod in his test.

Lowner wrote in post #16752929
If its an MFA issue, then mounting it on a tripod will not prove anything.

Manually focusing in live view would eliminate MFA as a potential culprit. Tripod makes it easier to zoom to 10x and manually focus, and eliminates camera movement as a variable.


In the first post, it looks like it's focused slightly behind the eyes. The earrings look crisper than the eyes.

Also, as I have gotten older I have developed the need to use reading glasses. I use several manual focus lenses. It is not terribly easy to focus through the viewfinder, even with the proper focusing screen for the 5DII.

I have found that I can use Live View in 1x, 5x, and then 10x with the Zacuto 3x loupe and I achieve accurate manual focus, without the need for glasses. The Zacuto includes a baseplate that provides a frame around the display on the camera so that you can snap the loupe into place on the camera. While this appears primarily intended for video shooters, I use this set up to focus Zeiss lenses, both handheld and tripod mounted.

Not directly related to the OP, but maybe helpful in general to the readers of this thread.

kirk