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scsambrook
Joined: 29 Mar 2009 Posts: 2167 Location: Glasgow Scotland
Expire: 2011-11-18
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Posted: Tue Aug 10, 2010 3:23 pm Post subject: MF focusing problems |
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scsambrook wrote:
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! _________________ Stephen
Equipment: Pentax DSLR for casual shooting, Lumix G1 and Fuji XE-1 for playing with old lenses, and Leica M8 because I still like the optical rangefinder system. |
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Univer
Joined: 30 Jun 2009 Posts: 282
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Posted: Tue Aug 10, 2010 6:40 pm Post subject: |
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Univer wrote:
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 |
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indianadinos
Joined: 06 Jul 2008 Posts: 1310 Location: Toulouse, France
Expire: 2011-12-05
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Posted: Tue Aug 10, 2010 6:56 pm Post subject: |
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indianadinos wrote:
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 _________________ Please visit my blogs Shooting with a Pentax K10D / FF Visions
Takumar: 24/3.5, 28/3.5, 35/2, 35/3.5, 50/1.4, 55/1.8, 85/1.8, 105/2.8, 120/2.8, 135/3.5, 150/4, 200/4
Pentax-K: M28/2.8, K28/3.5, M50/1.4, A50/1.7, M50/4 Macro, K85/1.8, K105/2.8, K135/2.5, M200/4, M70-150/4
Zeiss: Flektogon 20/2.8, 20/4, 35/2.4, 35/2.8, Tessar 50/2.8, Pancolar 50/1.8, Biotar 58/2, Sonnar 135/3.5, Sonnar 180/2.8
Meyer: Primagon 35/4.5, Domiplan 50/2.8, Oreston 50/1.8, Primoplan 58/1.9, Trioplan 100/2.8, Orestor 100/2.8, Orestor 135/2.8
Schacht/Steinheil: Travenar 90/2.8, Travenon 135/4.5, Quinar 135/2.8, Quinar 135/3.5
Russian: MIR 37B, Industar 50/3.5, Helios 44M & 44M-2, Jupiter 37A
P6: Flektogon 50/4, Biometar 80/2.8, Orestor 300/4
Nikkor: Nikkor-O 35/2, Micro 55/3.5, Nikkor-S 50/1.4, Nikkor-Q 135/2.8
Fuji: EBC 28/3.5, EBC 55/3.5 Macro, EBC 135/2.5
Misc Lenses: Kiron 105/2.8 Macro, Tamron SP90/2.5
... and a few other Vivitar, Tamron, Sigma and Soligor lenses ...
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Screamin Scott
Joined: 13 Oct 2007 Posts: 1014 Location: Dallas, Georgia USA
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Posted: Wed Aug 11, 2010 2:47 am Post subject: |
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Screamin Scott wrote:
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 _________________ Cameras-Nikon D300, D7100,D610,FE2,FTN ,FT2,N90s, Olympus Pen EP-3 & Olympus OM-D E-M10
Nikkor AF Zooms=28-105/3.5D,28-70/3.5D,35-135/3.5, et al
Nikkor AF //50/1.8,//Nikkor MF//50/2ai,50/1.8ais 50/1.4ai,24/2.8ais,28/2.8ai,28/3.5ai,55microAis/2.8,105/2.5ai,200/4ai,300/4.5ai35-135/3.5Ais,et al
Kiron /Kino made lenses//70-210/4ai,28-105/3.2ai,30-80/3.5ai,Viv 28/2ai,35-85/2.8aiVivS1,105/2.8Ais Dine,24-48/3.8ai VivS1,50-150/3.8aiViv,28-85/2.8aiViv,100/2.8Nai Viv,70-210/3.5Nai Viv,28/2.5ai Viv Komine made Viv//24/2Ais,135/2.8aiCF,28-50/3.5ai,28-90/2.8ai Viv S1,80-200/4.5aiCosina made Viv 19/3.8 Ais...Also Sigma 24/2.8 Ais Tokina made24/2.8ai VivAF Sigma 21-35/3.5,& other lenses... A link to some of my Flickr albums...
https://www.flickr.com/photos/screaminscott/albums |
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scsambrook
Joined: 29 Mar 2009 Posts: 2167 Location: Glasgow Scotland
Expire: 2011-11-18
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Posted: Wed Aug 11, 2010 12:16 pm Post subject: |
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scsambrook wrote:
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. _________________ Stephen
Equipment: Pentax DSLR for casual shooting, Lumix G1 and Fuji XE-1 for playing with old lenses, and Leica M8 because I still like the optical rangefinder system. |
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poilu
Joined: 26 Aug 2007 Posts: 10472 Location: Greece
Expire: 2019-08-29
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Posted: Wed Aug 11, 2010 12:50 pm Post subject: |
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poilu wrote:
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 _________________ T* |
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scsambrook
Joined: 29 Mar 2009 Posts: 2167 Location: Glasgow Scotland
Expire: 2011-11-18
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Posted: Wed Aug 11, 2010 3:15 pm Post subject: |
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scsambrook wrote:
poilu wrote: |
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 |
Poilu, thanks for those wise words and the link to the test chart. Indeed, you're absolutely right about screen registration and I had already checked it using what was probably the same chart. That reassured me that the camera is fine and, regretably, the problem is with my eyes' lack of visual acuity.
I was quite surprised to see how accurate and consistant the camera's AF mechanism actually is - although both my AF lenses are of modest apertures. The AF mechanism was far more consistant than I was with the 18 to 55 Pentax lens. In fact, at the shorter focal lengths it was AF ten points, my eye nil points ! _________________ Stephen
Equipment: Pentax DSLR for casual shooting, Lumix G1 and Fuji XE-1 for playing with old lenses, and Leica M8 because I still like the optical rangefinder system. |
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kuuan
Joined: 14 Jan 2008 Posts: 4569 Location: right now: Austria
Expire: 2014-12-26
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Posted: Wed Aug 11, 2010 3:55 pm Post subject: |
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kuuan wrote:
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! _________________ my photos on flickr: https://www.flickr.com/photos/kuuan/collections |
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