Dioptric Adjustment

TBath wrote in post #12363643
Been using cameras with an Diopitric Adjustment for years but until I read the the following I did not know how to adjust it correctly.

Link to Canon cheetsheet about Diopitric Adjustment

Thanks for this tip!

ever head of presbyopia?

http://en.wikipedia.or​g/wiki/Presbyopia

Starting in middle age, your eyes may begin to lose most of the elasticity needed to focus up close. However, it will still be possible to read with the help of the reading glasses. The Dioptric adjustment is build in reading glasses for us old farts that need a few diopters of correction to clearly see the image via the viewfinder plus all the settings. Very hard to hold you eye to the viewfinder with reading glasses on.

MCAsan wrote in post #12385153
ever head of presbyopia?

http://en.wikipedia.or​g/wiki/Presbyopia

Starting in middle age, your eyes may begin to lose most of the elasticity needed to focus up close. However, it will still be possible to read with the help of the reading glasses. The Dioptric adjustment is build in reading glasses for us old farts that need a few diopters of correction to clearly see the image via the viewfinder plus all the settings. Very hard to hold you eye to the viewfinder with reading glasses on.

Exactly! My eye sight is corrected with contacts to 20/15, but I need +2.00 reading glasses for up-close stuff.

Heck, you can't even see the diopter mark on the wheel on my cameras...both are in the 12 o clock position.

Jason C

I'm having an issue with the dioptric adjustment on my new T3i. I had no issues with my XTi but as soon as I looked in the T3i viewfinder it looked different. The manual says to adjust it until the AF points are sharp but they never get sharp, they always stay fuzzy. Only the box around them gets sharp and when I have it set there the image I'm seeing just doesn't look sharp.

For the record, I do not wear glasses and have no issues with my eyes.

sbattey wrote in post #12363422
I wear glasses...a fairly large pair that stick out from my face quite a bit.

I have no trouble looking through my viewfinder with them on, maybe that is just me though.

The bifocal argument...I could see that.

Me too.

Okay, so I just read through this thread and the Canon link.
I have the 7D and 5DII, and I wear glasses. I just found out that I had not correctly adjusted my diopters on either camera body. I have now properly set the diopters on both bodies (by 3 clicks on both bodies).

I wonder if this is going to make it easier to perform different types of focusing???

Such as 1. hyperfocal - 2.night focusing (which I have had issues with) - and 3. wide open focusing (which I also have had issues with).

Are any sure if this will help?

If you manually focus possibly.

Be aware though that you only see f4+ dof so you cannot (without changing the screen) ever know you have the right focus manually with fast lenses.

shane_c, you stated "I'm having an issue with the dioptric adjustment on my new T3i.T3i. I had no issues with my XTi." How much time has elapsed since you used the XTi and acquired the T3i. It may very well be that you have developed presbyopia (see the input right above yours) in that interval.

John from PA wrote in post #13791776
shane_c, you stated "I'm having an issue with the dioptric adjustment on my new T3i.T3i. I had no issues with my XTi." How much time has elapsed since you used the XTi and acquired the T3i. It may very well be that you have developed presbyopia (see the input right above yours) in that interval.

Just a few days. I still have the XTi so got it out and the dots and boxes around them are sharp. Look in the T3i and the boxes are sharp but the dots are fuzzy.

I brought the T3i with me to work today to try it under better lighting. Where I live it's all trees so it's sometimes hard to see how sharp they are in the viewfinder, especially with the wind making my eyes water.

But regardless, the dots don't get sharp they stay fuzzy but the boxes are sharp.

shane_c, is the viewfinder clean on the T3i? Really should not be any major difference in the two cameras.

John from PA wrote in post #13793670
shane_c, is the viewfinder clean on the T3i? Really should not be any major difference in the two cameras.

yes

This could be something as simple as a slightly misaligned mirror or focus screen. If either are even slightly out of proper location it could in theory cause this.

If the camera is new, why not take it back to the shop and try another one before worrying too much?

Think of the dioptric adjustment as reading glasses for us old farts with presbyopia.


http://en.wikipedia.or​g/wiki/Presbyopia

I think I figured out my "problem".

I got both cameras out tonight and brought up the white screen of MS Word. From sitting up close and staring through the viewfinder it became clear that it looks like the AF dots are different.

XTi - I turned the dioptric and it makes the whole dot sharp

T3i - once I started turning it I could now see (thanks MS Word) that there was a little tiny dot inside the bigger circle. So I made that sharp now and there is a small fuzzy haze around it. But there is a little dot there and it's now sharp.