MF focusing problems

[scsambrook]

I'm finding it harder to get the focusing 'spot on' with my MF lenses on my Pentax K10D. Does anyone have any experience of the focusing screens supplied by the firm Focusing Screen.com (http://www.focusingscreen.com/index.php).

They look to supply exactly what I want, a split image with a grid, and the prices seem quite reasonable.

Any other suggestions for reliable supliers would be welcome!

[Univer]

Hi Stephen,

Your experience sounds uncannily like my own - with respect to the K20D, in my case, rather than the K10D.

For my first year of ownership, I seemed to have little difficulty nailing focus with the stock screen, and the focus confirmation signal seemed to be reliably accurate. (I say "seemed" only because I suppose it's barely possible that the problems were there all along, but that I was unnaturally lucky the whole time.) But recently, I began to get an unacceptably high percentage of shots where focus was missed entirely.

I asked about the issue at pentaxforums, and there were a few reasonable responses mixed in with the usual irrelevancies (I had to keep reminding people that I was not using AF lenses!). I did learn that the K20D has a reputation for front-focusing with AF glass (that would affect the focus-confirmation signal as well), but that didn't and doesn't explain why this phenomenon seemed to manifest itself after months of problem-free shooting.

In the end, I wound up sending my camera to KatzEye to have a split-screen installed. The experience was among the very best consumer/vendor interactions I have ever had, and I would recommend KatzEye without reservation. (In fact, I did - right here.) The split-screen has definitely helped, although I now find myself in the interesting position of having to re-learn how to focus with the sort of screen I used in my film days - when my eyes were younger.

I was also able to use the split-screen as a diagnostic aid in adjusting the K20D's AF system (in order to restore the reliability of the focus-confirmation signal). I've managed to get it very close indeed - to a point where I'm confident any further fiddling on my part will serve only to make things worse.

Your issue may have nothing to do with focus confirmation, of course. But I find it interesting that we both went along without difficulties for a time, and then began to see a problem.

In any case: two hearty thumbs up for KatzEye. I do hope you get this sorted out! If you turn up any answers, I would be most interested in hearing them.

Cheers,

Jon

[indianadinos]

Hi,

+1 for Katzeye ... I have used MF lenses with the original K10D screen and with two cheap "split-image" screens, all with a focusing error rate quite high ...
Now, with a Katzeye on my K10D, most of my blurred photos are blurred because of micro-motion, not because of focusing issues ...

The build quality of the Katzeye is much better than the others, the thirds lines don't look as if they were traced with a pen ...

So, my suggestion: if you can't afford a Katzeye right now, keep saving your money and go for it, you will never be disappointed ...

Hope this helps ...

Cheers

[Screamin Scott]

I got a "cheap" split image screen from a reseller on eBay thru focusingscreen.net...I installed it myself & I have had no problems like others have said of the cheap screens. Most of the screens are cut down versions of older MF screens from Canon, Nikon & Minolta...I didn't need the shim they supplied either

[scsambrook]

Thanks to all who've responded so far - comments much appreciated.

My favourite MF lens is a 90mm Tamron SP. I have no problems using it for flower heads and other subjects up close - say, under two feet (or half a meter). And infinity's fine as well, because you can hardly go wrong there! The difficulties start beyond three feet, especially if I'm using wide apertures and there's relatively little depth of field. Then, I regularly miss the critical spot by just enough to cause problems. My spectacle lens prescription is up to date, and I check to make sure the camera eyepiece is adjusted properly. If it gets moved accidentally by even one click, then even close ups are often mis-focused.

Using my 50mm Pentax SMC-A lens is even more problematical - beyond two feet I don't even try these days.

I only have two AF lenses, the cheap 18-55 that came with the camera and a Sigma 55-200 I got on eBay at an unbelievably silly price. Both of them work fine in AF mode - no front or back focus problems at all. If there's enough light and contrast for the AF to work, they do better than I can. Although I have learned to set the Pentax lens to 55mm to focus and then zoom back to make the shot.

Sometimes, I'm tempted to give up trying and buy a decent AF Macro lens, but the last thing I want is to expel myself from the world of MF. So I guess it's time to research KatzEye. Then maybe I can start to use the box full of other MF lenses which are sitting largely unused.

[poilu]

you must check if you screen registration distance is correct
if it is out, even the best eye cannot focus
if it is ok, pratice is the key to success
use this card to find out
http://focustestchart.com/chart.html

[scsambrook]

[kuuan]

Stephen it is not easy to focus on a dSLR with the small viewfinder of an APS-C sensor camera, that's for sure!

Without both a split focus screen and the viewfinder magnifier I wouldn't get many photos focused neither.
My *istDs has a cheap chinese split focus screen ( jinfinance ), my K-x a Katz Eye.
The Katz Eye is brighter and has a grid which helps me leveling, I like the split screen portion being diagonal on the chinese. ( there may be 'diagonal' Katz eye screen available too )
The viewfinder magnifier is the original Pentax called 'Pentax Magnifying Eyecup O-ME53'

Don't blame your eyes. Try using both, split focus screen and viewfinder magnifying glass, they are of great help!