PDA

View Full Version : Focus Frustration



aubintbay
12-13-2010, 01:33 PM
Hey all. I have been having a problem getting the focus right in my photos right from day 1.:sad: The problem I think is that I wear glasses. Not just for reading but for everything! My current specs have the progressive lenses which may be a big part of my problem. I have noticed that the autofocus misses sometimes (probably due to some of my own issues i'm sure):wall-an: but in the end I would prefer do do most of the focus work manually which has frustrated me greatly thus far. I have tried adjusting the diopter on the camera and that helps but has not been "the" answer. I find that using "live view" where I can stand back so to speak and look at a magnified image helps but that is just not practical on anything but a landscape. I have decided that my next pair of specs will be bi-focals with the visible line across the lenses which will hopefully eliminate alot of the problem. Lack of practice has not been a problem either. I try and get out as often as possible.

Any suggestions would be greatly appreciated.

Aubrey

Iguanasan
12-13-2010, 03:09 PM
I haven't tried this with my XSi but I used to have this on my Canon TX film camera. It's called a focusing screen, Focusing screen - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Focusing_screen) , and as I understand it you can get them for your DSLR too. Found this one on the 'net quickly via Google... this is not a recommendation, just one particular site I found: Canon 450D (Rebel XSi) Focusing Screen - KatzEye Optics (http://www.katzeyeoptics.com/item--Canon-450D-(Rebel-XSi)-Focusing-Screen--prod_450D.html)

This way, you are not so much trying to gauge focus but see when the image is in proper alignment. This might make focusing a lot easier.

Anyone else have any experience with these things?

Richard
12-14-2010, 09:36 AM
On my xsi, 99% use centre point focus auto focus. (My eye sights not great). I also use the back button custom focus. When I switch the lens to manual focus and hold the rear button focus....

each focus point lights up as it detect sharpness. (I'm not sure if it does the same if you hold the shutter half way?)

Marko
12-14-2010, 10:03 AM
I'd suggest that the first step is using a known reference point to test sharpness. At least that way you'll know if it's you or not.
Tape newspaper to a wall, put the camera on a tripod, (VR or IS OFF if the lens has it) and focus on the print so that it is tack sharp. Test all the apertures. Use a cable release or self timer and focus manually. Then evaluate the image on your computer.
If you are shooting RAW you will have to sharpen the image somewhat, but if the focus was right, it should still be pretty sharp. Once that's done then I probably would look into those bifocals as focusing on near objects OR far objects should be easier. I'd ask my eye doctor though and maybe do additional searches on photography with bifocals.
Hope that helps.

aubintbay
12-14-2010, 02:05 PM
Hey guys.....thanks for good suggestions.
I have been working on the focus by taping a few pages to the wall and trying it that way and will continue. What I have noticed is that after autofocus if i go to live view and magnify 10x i can tweak the focus. If I have the time I can almost get the right focus manually but that time tends to blow the opportunity if you know what I mean.
It turns out one of the people I work with has a focus check with a ruler that lays on an angle in it and he is a bit of a photo buff so I may have some in house help.....nice.
Like richard I also tend to do most things with just the centre focus point... and then just work with other settings in either aperture or shutter control for almost everything.
I think I need to continue to practice these and develop a routine of sorts that I can duplicate repeatedly.
The glasses are an issue that I will definitely deal with. I know from experience sitting at my desk that if I don't feel like moving all I need to do is tilt my head slightly and I can read things across the desk without picking them up. (But I'm not lazy eh!!) So if my glasses are just slightly moved it could may a difference.

Thanks again...Aubrey

Kawarthabob
12-14-2010, 03:53 PM
I havn't tried this but saw it on scott kelby's site where they suggest removing the lense and adjusting the diopter until the focus points are clear for your eyesight.

edbayani11
12-15-2010, 11:06 AM
i had the same problem and i tried removing the lens and adjusting the diopter until the focus points markers became sharp but it did not focus well since my eyes needed a stronger grade. i went to an optical shop and asked the technician so that i could use their lenses that they use for testing eyes and i used it by putting it over the eyepiece of the camera, without the lens until i found one that focused the markings. i then put on the lens and tried focusing with it and it was sharp. i asked the technician what grade the lens that i used and ordered a pair and asked him to grind it so that it fits the eyepiece.

JAS_Photo
12-15-2010, 07:16 PM
I also wear progressive lenses and have astigmatism so focusing for me was always a problem- the old way with the cross hairs- i always felt i was correcting my own vision. Thank goodness for autofocus lenses. This article gives a few hints on getting sharper focus.

Advanced Tips for Tack Sharp Images (http://networkedblogs.com/bSmbB)

I think that today's autofocus cameras are pretty damned accurate, to the point that you can make those "Hail Mary" shots and get a sharp focus. I have seen Joe McNally do it a few times! I know I have picked up my camera to take a quick photo when I was not even wearing glasses and it focused sharply for me.

Ok, so I am going to pretend you are totally new to photography and just mention a few things. One is holding the camera steady, with your arms close in and taking a breath then slowly releasing the shutter. Oh, heck let's do the grip aka Da Grip


http://www.youtube.com/watch?v=EDsx3-FWfwk

When taking photos at low shutters speeds of subjects likely to move, pressing the shutter for three quick frames may result in one that is very sharp.

I also have my camera set up for backfocus as explained in the article and I prefer to use the 52 points of focus that my camera has. It's not the quickest way so may not always be the best way but if you are working with a tripod and taking your time, it is very accurate. Also, use a tripod when you can!

Hope something here proves helpful!

Yisehaq
12-16-2010, 02:00 AM
I used to have focus problems too. One thing I found very helpful is to get used to the focus confirmation light in the view finder. Sometimes, when you think that you have got the focus, due to many reasons, it will still be blinking. Make sure it has stopped blinking before you take the shot. That has really improved focusing for me.

Iguanasan
12-16-2010, 09:07 AM
Thanks for sharing that YouTube video, JAS. Funnily enough, someone was talking about that very technique last night at my photo club meeting :)

aubintbay
12-19-2010, 08:24 PM
Thank you all for the good info.
As it happens someone else has also suggested taking a few shots in burst mode to see if that helps so i will be having a go at that. I had a look at the Joe Mcnally video.....several times. Its reassuring to know that he has to work at it too.
You have a good point there Yishaq about the focus confirmation light.....I had pretty much forgotten that it was there.
I think I can safely say I will be pretty busy the next few months trying to improve on this. (if not forever!!)
Thanks.