06-26-2014 02:44 PM
Your conclusions regarding autofocus accuracy are not universally held by many reputable reviewers. Depending on the review, I've read that the f1.8 focuses more accurately than than the f1.4. All reviews mention that it isn't the quietest lens when focusing.
06-26-2014 03:19 PM
Just wow, thanks so much for all the detailed responses!
The 50mm I’m using is the 1.8 II, and I was fully aware that it isn’t a “pro” lens by any means when I got it. It’s really embarrassing, but I’m not at the right place financially to be able to afford new/better lenses. If I had known the time I got my inheritance, I would have invested in a cheaper camera and better lenses instead of the other way around. Big rookie mistake, but I really thought I’d be able to afford better lenses eventually.
As for focus mode, I primarily use one shot.
I had no idea the hidden assist points only worked in AI servo, thanks so much for that! It’s really time I sat down with the manual, isn’t it I’ll try to use live view more when I’m photographing products, maybe that’ll help some.
I rarely use large apertures, which is why the focusing issue is such an annoyance for me. I can’t get macro with my 17-40mm, so I’m always a good distance from what I’m photographing, and using F8-16 usually. Also I do usually take the shots on a white plexi table, so there shouldn’t be any problems with getting the camera to focus on the item.
When using the lenscal I was about 2 metres away, the instructions said 30-50x the focal length but I didn’t have much more space to work with. Honestly with the 17-40mm I only did one or two tests, as the calibrating tool was too far away to accurately see, even when zooming in. The whole thing looked out of focus every single time. What I mean by that is that my entire image is slightly fuzzy, like nothing is in perfect focus. I’ll try to take my setup outdoors as soon as I can and see if that gives me a better result!
That’s what I thought too, f11 should be “safe”, but some times it isn’t. And the fact that nothing in the picture looks like it’s in focus just makes me more certain it’s either a camera or user error, not anything to do with the lenses. I’ve also used the 17-40mm on the 10d, 20d and an old analog camera without any of these issues.
I’ll try cleaning the contacts, thanks for the tip!
I just had the sensor cleaned, I’ve been thinking of replacing my focusing screen with the eg-s, is that the same as af sensor array? Like I mentioned, I’m really not good technically
I do love to view at 100% when I’m being extra picky, but usually I view them at a nice “working size”, so about 50-60%
I know Brigde _always_ shows my images blurry, I have to open them in photoshop to get a more accurate view. I sometimes use lightroom, but usually I stick with photoshop (CC)
I used a pola filter, but had the same thought that maybe it was affecting the outcome (and from what I understand it does make a little less light go through the lens) so I did tests without it and had the same results.
I will absolutely try live view more though, I really had no idea the focusing was different with it.
Thanks guys so much! I will continue with tests and try all your advice!
06-26-2014 03:30 PM - edited 06-26-2014 03:47 PM
I wish you the best of luck and as I have a number of f/4 constant aperature lenses, I wanted to add that I believe you should be getting excellent results most of the time with these lenses. The 5DII isn't the latest or the greatest but a solid camera with excellent mechanical capabilities, however it might not be the best choice for those demanding faster, more accurate, autofocus or for low light work.
We didn't cover the topic of AF assist lamps. The 5DII has none but you could rely on a lamp built in to a compatible speedlite.
06-26-2014 06:32 PM
...., I’ve been thinking of replacing my focusing screen with the eg-s, is that the same as af sensor array? ...
No, the focus screen is separate from the AF sensor array.
The EG-S screen might help you manually focus your f1.8 lens, but doesn't help much with anything with less than f2.8, so won't be of much use with the 17-40. It's primarily useful for manual focus (or visually confirming auto focus), but won't directly effect or improve autofocus accuracy at all.
Another thing that occured to me is your computer monitor could be at fault. I'd expect all photos to appear similarly out of focus, if that were the case... not just some percentage OOF and others fine. You mgiht be able to check and rule it out by making some prints from images that appear OOF on screen. If the prints also look soft, your monitor is fine. If howver they are sharp, you've got a problem with the monitor.
I was just passing along a lot of what I've heard and read about the 50/1.8 focusing. I'm always a bit skeptical about reviews and online feedback... who knows the person's level of experience. For example, if they have never shot with a USM lens, they might think a micro motor lens like the 50/1.8 is the best it can get. The clincher for me regarding the 50/1.8 was so many people on another forum reporting difficulty doing a Micro Focus Adjustment with it.
I still think the 50/1.8 II is a great little lens, considering price and potential image quality. I'm not dissing it. Just sayin' that I wouldn't expect to get as consistent results with it as I would with the 50/1.4 USM (which I do use extensively).
I don't know your level of experience, but something else you might find useful is an excellent tutorial about Canon Auto Focus that B&H Photo has posted on YouTube. It's a three part series, each about half an hour long, presented by Canon's Rudy Winston. The first of the three vids is at http://www.youtube.com/watch?v=iAx86nblZ2g These are a few years old now, but still relevant and the 5DII is one model that's discussed. May be worth your time to view. I imagine you could find more on the Canon Learning Center, too.
06-27-2014 01:16 AM
I'll read up on teh AF sensor array then, thanks!
That's what I thought about the autofocus and the EG-s screen.
I view my photos on 2 screens, my imac at home and an Eizo screen at work, so I don't think there is anything wrong there. I'll get some printed just to check though, thanks for the tip
Of course, if I had the funds I would have gotten the 50/1.4, but for photographing products to put on a website, the little 50/1.8 II gives more than good enough photos (when they are in focus that is). But when I do my own personal work, I need more from my camera/lenses than what I feel I'm getting now. Photographing people, it's so typical if one of the best shots are blurry.
As for my level of experience, I did attend the norwegian school of photography for 2 years, though that is some years ago now. I feel I am an experienced photographer with very limited technical knowledge. I've never had issues with my gear before, I'm used to putting my camera to work and getting great results, which is why I'm so flustrered when something does happen. I don't have a service center near me either, I'd have to ship my camera off to get it looked at by professionals.
I'll still take a look at the videos, it may be time to refresh some knowlede and maybe give it another go at learning more about what makes my camera tick. Thanks so much again