85mm f/1.8 problem, please advise!

Hi there -

I've got an 85 1.8 that I haven't been too thrilled with since I bought it new in Nov. 2014.

It has never seems to focus right or give me sharp images I thought I could expect from this lens. I'm not the greatest photographer in the world or anything, but my keeper rate seems really low with this lens. I've been waiting to get some lighting and a better target setup to be able to do a FoCal AFMA calibration and I was finally able to do it last night. I also happened to use the new version of the software. I took advantage of Reikan giving free access for two weeks to their service that compares your camera/lens results to those of other uses with the same combo.

I tested my Tamron 24-70 f/2.8 and my 85 f/1.8 last night and the 85's results were.... weird. I'm not exactly sure what it means, or what could be the problem. The lens is still under warranty and I wondered if this was something I could get it sent in/repaired for. My Tamron on the other hand tested pretty normal.

Here's the overall results from my 85's Aperture Sharpness test:

how about some photo samples...

I haven't used it all that much lately, my most recent shots are probably these:
https://photography-on-the.net …32&mg=108139&i=​i105291447

I've been avoiding using it because I'm rarely happy with the results. My nifty-50 is better. I tried to use it the other day and have some photos, but I haven't got them off the card yet and can't right this moment.

Thanks

I saw you had 1/80th of a second in the one shot. Unless you have a really steady hand, i'd at least using double the ss of my focal length (in this case at least 1/160 or faster ss). It seems like motion blur to me in those pics except the first one looks a bit sharper than the rest.

Thanks for looking at those and giving me your opinion, appreciate it. I realize I did some things wrong with those shots.

I'm curious though, regardless of my images taken with the lens, anyone care to take a look at charts and give me your opinion on what's going on here... How is it possible that my sharpest aperture is f/10? Pretty sure that's not normal, and then the sharp drop off from f/8 down to 1.8?!? I don't think this lens is ok. Not that ALL my stuff turns out sharp, but I was expecting better from this lens, at least from what I have read... This lens has never impressed me.

Thanks

(edit) Wanted to add I got repeatable results and also that my Tamron came in pretty "normal".

Tamron Aperture Sharpness @ 24mm:

Check this out, talks about astigmatism in lenses.

http://www.cambridgein​colour.com …uality-mtf-resolution.htm

This is one of the best websites for technical photograpy related questions, ever.

I think you should be sending the lens back for Canon to take a look.

You seem to be preFocusing.
My 85 1.8 is extremely sharp and I love it for night deep sky photography same as portrait.

Left Handed Brisket wrote in post #17487454
Check this out, talks about astigmatism in lenses.

http://www.cambridgein​colour.com …uality-mtf-resolution.htm

This is one of the best websites for technical photograpy related questions, ever.

I think you should be sending the lens back for Canon to take a look.

Thanks I'll give this a read! I want to say that you've sent me here before, but not for this topic.

samsen wrote in post #17487483
You seem to be preFocusing.
My 85 1.8 is extremely sharp and I love it for night deep sky photography same as portrait.

I can't say for sure that I didn't do that here, or that I've never done that, but I RARELY do that. I'm usually trying to use ai-servo because of my kids. Of course all my FoCal stuff was on a tripod, one shot.

I don't know what your experience is, but maybe the 85mm is just one of those lenses the more you use it the more keepers you get.I have a 85mm f/1.8 and I find it an outstanding lens on all my cameras including my EOS M, right up there with my 135L.

Definitely not experienced, but that is why I'm partially relying on FoCal. The fact that my lens behaves so differently than an average 85 1.8 just reinforces my feeling that my version hasn't impressed.

In this thread I'm really looking for confirmation, based on the FoCal data that something isn't right. I'm also wondering about the astigmatism chart and how it may relate. Finally, I'm curious how or what I say to Canon to get this fixed under warranty.

Lets eliminate autofocus from the equation and a few other things.

Put the 6d and the 85mm on a tripod with its legs retracted. It'll be more stable that way. Use a cable release rather than the shutter and focus on your target manually by using Live View. Ensure there is enough light so your shutter time is 1/160th or faster. Use your DOF preview button when you focus (just in case there is focus shift).

If you compare your manual focus results with the autofocus results, it'll be easier to come to conclusions.

I think the users here pretty much agree with Focal's data subscription graph (i should do this test at some point!)

It should be sharp after microadjust. My first copy had too much back focus and I sent it back to the vendor for a replacement. The replacement was better, but not perfect. The lens should give you maximum sharpness at about F4 or F5.6 or so.
How does it do at F2.8? It should be sharp there. My normal test is a close portrait, and I focus on the near eye with most lenses. The 85 has very shallow depth of field wide open, so if AF is off, your photos won't be sharp enough.

DoughnutPhoto wrote in post #17487726
Lets eliminate autofocus from the equation and a few other things.

Put the 6d and the 85mm on a tripod with its legs retracted. It'll be more stable that way. Use a cable release rather than the shutter and focus on your target manually by using Live View. Ensure there is enough light so your shutter time is 1/160th or faster. Use your DOF preview button when you focus (just in case there is focus shift).

If you compare your manual focus results with the autofocus results, it'll be easier to come to conclusions.

I think the users here pretty much agree with Focal's data subscription graph (i should do this test at some point!)

Good idea DoughnutPhoto - I'll try and do this tonight and take a look at the difference. Regarding the data subscription - I agree, it's pretty handy. You can pay for it monthly and yearly - I can see myself picking up a monthly sub here and there when I get a new lens or if I suspect I'm having issues. I wish it wasn't subscription based though.

artyH wrote in post #17487996
It should be sharp after microadjust. My first copy had too much back focus and I sent it back to the vendor for a replacement. The replacement was better, but not perfect. The lens should give you maximum sharpness at about F4 or F5.6 or so.
How does it do at F2.8? It should be sharp there. My normal test is a close portrait, and I focus on the near eye with most lenses. The 85 has very shallow depth of field wide open, so if AF is off, your photos won't be sharp enough.

Hi artyH - I was expecting something similar (max sharpness between 3.2 and 5.6 some place). As far as my copy goes, at f/2.8, I've got sharp shots before but generally have been pretty disappointed with this lens, which was surprising to me because people seem to love it in general. I have used this lens for close-ish portrait, but I almost always manually focus those shots.

I went back through some of my shots on Zenfolio and found a couple examples where I was ok with the results:

Auto-focus

You really should try and get that shutter speed up

I agree DreDaze. What do you think I should be aiming for? I realize this is probably different for everyone based on skill and how steady you are, but in general? 1/250? I still think something is up with this lens, but I've started to realize the same about some of my shots so I've been trying to go manual mode, setting my aperture and shutter speed, with automatic iso.

To be completely honest I probably would have kept going on about my business with this 85, accepting a low keeper rate compared to ALL my other lenses, but hooking it up to FoCal the other night made me think that maybe something else was going on that was having some affect.