Reading glasses and focussing

[baldwin8]

After a decade break from shooting, I have gotten back by buying a DSLR Sony A350.

The problem is now I wear reading glasses and still like using the viewfinder but I don't wear my glasses when using it. I am finding a lot of my images somewhat soft. Many of my subjects are railroad and aircraft taxing at the airport where I work.

I switch between autofocus and manual focus trying to find the best result but still not completely happy.

I would appreciate hearing from anyone with similar problems.

Thank you for reading.

[amk1977]

Hi,

Just a thought but, have you adjusted your diopter next to the viewfinder?

[baldwin8]

Yes, it was the first thing I did when I was setting up the camera. Everything inside the viewfinder is very clear.

[amk1977]

Ok, I just thought I'd eliminate the obvious first lol.

The only other thing I can think of is the shooting mode and AF modes you are using when shooting. If you have it in anything other than aperture priority or manual, then the camera will be selecting the aperture automatically. If this is the case then it may be shooting wide open, or close to it, which quite often will result in less than spectacular images. In general, a lens' optimum sharpness is around f/8-f/11. Try shooting in "A" mode and stopping the lens down and see if the results are better.

Also, if the planes are not stationary, make sure you have the camera set to AF-C or continuous focus, otherwise you run the risk of the subject moving out of focus, especially if they are taxiing towards or away from you.

You don't mention what lens(es) you are using?

[baldwin8]

Thank you for the help. I have changed the Auto focus to continuous mode as it was not the default.

The camera I have has the 18-70mm that came with it. It does say it is a camera but from what I have read it should be okay for non close up work. Or am I wrong on this? I like the focal range it allows me for the subjects I am shooting.

Normally I find that about one in five shots are good enough to edit for sharpness. Maybe this is the normal, I don't know.

I still have to experiment a lot more but I was very curious about my reading glasses issue.

Thank you for reading.

[GeoffWessex]

My problem with reading glasses was made worse when I started using a manual focus lens - great lens and great value (nobody wants a manual lens) but I found some advice about the dioptre, as mentioned above.... It's just a matter of looking squarely through the viewfinder (half the time we look over the top) and 'tuning' the viewfinder information digits/letters. Once they're sharp we need to keep using the reading glasses in that 'square-on' fashion and avoid peering over the top of the lens.
I've a feeling that people who use bi-focals are in a worse situation.

[KeithT]

I wear reading glasses and have a special pair made for computer screen distance. I find that adjusting the viewfinder diopter works for me. I think you can also get diopters for your viewfinder to suit your eyes as an accessorie.

Here's Nikon and Can diopters.

http://www.warehouseexpress.com/view...3061-m168-r141

http://www.warehouseexpress.com/buy-...s-e-3/p1011401

[cosmicma]

hang on a sec am i missing something ???

ok manual focus i can see there being a bit of a problem there but autofocus issues ??

with the camera set to auto focus anything you point the camera at ( within reason ) should be in focus and should have nothing to do with view finders , diopter settings or the condition of you eyes

if you find all your photo's are soft regardless of auto / manual focus i would sugest there's a problem with the camera or the lens
have you tried a different lens to see how that behaves ? or your lens on a different body to see if there's a difference

sounds more like a warrenty issue than a settings issue

[GeoffWessex]

It's not really a problem of soft or sharp focus on the subject..... it's the risk of focusing on the wrong thing! Try swinging your camera around quickly to focus on a small bird in a tree, for example - you'll get several shots or nice sharp twigs and leaves and a blurry bird.

Yesterday I was photographing somebody demonstrating basic techniques in playing the trumpet (he wanted pictures in a lecture handout he was making). This was in my makeshift studio, with tripod and lighting (not flash). I had a whole series of good shots and it all worked out well..... until I ran them all through Camera Raw. I had one shot of just the trumpet being held and I'd just let the camera auto-focus.... mistake! - the lens (even on centre-weighted focusing) managed to find a gap right through the trumpet and on the backcloth. I wasn't looking as closely as I had been and got a sharp backcloth and blurred trumpet.

[OliverJohnson]

The problem might be down to the size of the subject in relation to the AF point(s) selected.

You mention that you are using an 18-70mm lens which, assuming presumably means that you aren't very close to the runway, means that a plane is going to appear quite small in the frame. You don't mention what AF point you are using but if it's more than one then the total AF area is going to be larger than the subject meaning that the camera will try to focus on the background as well. Using a single AF point will help but if the plane is still small in the frame then even a single AF point may cover an area larger than the plane causing the same problem. What you may find more reliable (other than buying a longer lens) is to prefocus at a set point on the runway and pressing the shutter release when the plane reaches it.

As for using continuous focusing modes, a plane taxing at a slow speed shouldn't really cause any focusing issues unless you are using a very large aperture like f/2.8 and even then you would have to be standing right next to the runway at the focal lengths you are using. A plane going down the runway as it takes off will obviously be traveling a lot faster and that might benefit from a continuous focusing mode but only if the plane is traveling away or towards you (not parallel with you) and again only if the plane clearly covers all the active AF points. If not continuous focusing may make the problem worse.

The other thing that might be causing the problem is if you are only getting a shutter speed of less than 1/125th (possibly 1/250th or more if the plane is taking off). At distance or even close up when using a large aperture this could be slow enough to cause some blurring of the subject. To avoid this try either increasing your ISO or use a larger aperture but be aware that the larger the aperture the shallower the depth of field but this should only be a problem if you are close to the planes as they taxi.

HTH