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Screamin Scott
Joined: 13 Oct 2007
Posts: 1014
Location: Dallas, Georgia USA
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 Posted: Sun Apr 19, 2009 3:34 pm Post subject: Checking focus after new focus screen installation |
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Screamin Scott wrote:
Other than the "ruler" test, what other tests can I do to check for possible front or back focus issues?...I have taken some macro shots, but with such shallow dof, I'm not sure if I have any focus issues or not. I also tried out an AF lens & that seems ok,...With the ruler test ,what guidelines as to camera placement do I need to follow. The reason I ask is that I got one of the Chinese screen & it came with an extra shim & I'm not sure it's needed. The screen came from focusingscreen.net eBay store & it had an additional screen. However, from the online installation instructions from them it appears that the shim may only be needed with a different screen than the one I installed....I did a "Google "translation of the page but that is of limited value...The installation went pretty easy & I replaced the brass (?) shim that was with the original screen. The split prism isn't exactly centered in the central portion of the 3mm circle in the middle of the viewfinder, but it's close enough...
_________________
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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GrahamNR17
Joined: 17 Jan 2009
Posts: 1855
Location: Norfolk, UK
Expire: 2012-09-06
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| Posted: Sun Apr 19, 2009 3:58 pm Post subject: |
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GrahamNR17 wrote:
Download this, print out the two test targets, then read the instructions until you really understand them. Should show up any anomolies 
http://graham.hopto.org/mflenses/focus21.pdf
It helped me uncover a few lenses with skewed elements, and a camera that was back-focusing.
Hope that helps,
graham |
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martinsmith99
Joined: 31 Aug 2008
Posts: 6950
Location: S Glos, UK
Expire: 2013-11-18
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| Posted: Tue Apr 21, 2009 11:27 am Post subject: |
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martinsmith99 wrote:
Cheap split prisms always seem to be off-centre. For the price of mine compared to the Katz Eye, I can live with it. 
Mine agrees with my chipped adapters at 50 & less FL but my 135s upwards there is conflict between the two. I have learned the hardway that the chipped adapters are not as accurate as the focus screen.
Graham> Thanks for posting that test. I'll give it a try.
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Casual attendance these days |
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naplam
Joined: 22 Mar 2007
Posts: 469
Location: Spain
Expire: 2013-11-30
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| Posted: Tue Apr 21, 2009 5:09 pm Post subject: |
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naplam wrote:
The one I bought for my Canon from ebay (seller jiakgong), came in a box that says focusingscreen.net so I guess it's the same manufacturer. Mine came with no extra shims. I removed the screen in my camera, which had a shim below already, and kept the shim in the camera, and it works great. Anyway, I think the effect of such thin shims is minimal, maybe it's even difficult to tell if the shim is there. |
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my_photography
Joined: 03 Nov 2008
Posts: 2772
Location: Pearl of the Orient
Expire: 2016-12-25
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| Posted: Thu Apr 23, 2009 2:38 am Post subject: |
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my_photography wrote:
Remember to "recalibrate" your dioptre after installing the split screen. I forgot that and most (maybe 90%) of my photos even at f4.5/5.6 were out of focus. Now, I have tested f1.4 and it can be spot on a lot of the times.
_________________
Zeiss: CJZ Flektogon 20/2.8, CJZ Flektogon 20/4, , CJZ Pentacon 29/2.8, CJZ Flektogon 35/2.4, CJZ Pancolar 50/1.8, Tessar 50/2.8, Biotar 7.5cm/1.5, CJZ Pancolar 80/1.8, CJZ Sonnar 135/3.5, CJZ Pentacon 135/2.8 CJZ Sonnar 200/2.8
Other Germany: Meyer Primoplan 50/1.8, Meyer Trioplan 100/2.8
Takumar: SMC 50/1.4 Super Tak 55/2, Super Tak 85/1.9, S-M-C 135/3.5, Super Tak 150/4
Russian: Zenith 16/2.8, Mir-24M 2/35, Volna-9 50/2.8, Helios 44M (58/2), Helios 44M-3 MC (58/2), Helios 40 (85/1.5), Tair 11A (135/2.8 )
Others: Sears 28/2.8, Sankor 35/2.8, Enna M�nchen Tele-Ennalyt 135/3.5
Zoom Sigma Zoom 28-85/3.5-4.5
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rawhead
Joined: 09 Feb 2009
Posts: 1525
Location: Boston, MA
Expire: 2014-04-29
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| Posted: Thu Apr 23, 2009 4:56 am Post subject: |
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rawhead wrote:
| naplam wrote: |
| The one I bought for my Canon from ebay (seller jiakgong), came in a box that says focusingscreen.net so I guess it's the same manufacturer. Mine came with no extra shims. I removed the screen in my camera, which had a shim below already, and kept the shim in the camera, and it works great. Anyway, I think the effect of such thin shims is minimal, maybe it's even difficult to tell if the shim is there. |
I must say, you are quite wrong. I got a KatzEye for my K20D, and then and only then did I realize that my K20D had "severe" front focus issue with the manual focus (i.e., the view finder screen, NOT the AF).
The solution? Swap the 0.15mm shim that was pre-installed at the factory for a 0.30mm one. Mind you, those 0.15mm contributed to the "severe" front focus (showing up as a 10~12mm front focus, shooting a 50mm f1.4 lens from around 35cm away).
The shims come in 0.05mm increments.
So, believe me when I say, you WILL know if the shim is not there 
_________________
Sony α7R, Pentax 67II, Kiev-60, Hasselblad 203FE, 903SWC, Graflex Norita 66, Mamiya M645 1000s, Burke & James 8x10, Graflex Pacemaker Speed Graphic (4x5 and 3x4), Century Graphic (2x3), R.B. Graflex Seried D, Rolleiflex SL66E, Rolleiflex 2.8C Xenotar, Mamiya C330f, a few M42, six P6, three OM, four Hasselblad, two Pentax 67, two Mamiya 645, one Noritar, and a sprinkle of EF. Oh, and an Aero Ektar and Leica Noctilux |
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my_photography
Joined: 03 Nov 2008
Posts: 2772
Location: Pearl of the Orient
Expire: 2016-12-25
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| Posted: Thu Apr 23, 2009 5:44 am Post subject: |
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my_photography wrote:
The shim is very important. Here is my quite unfortune experience.
I removed my focusing screen to clean it a few weeks ago. Something that was supposely quite simple after reading the internet and seeing some photos/illustration. Unfortunately, the author of the photos did not warn about the shim. Pushing the hold click, the screens and the slims came out. Any way, I tried to put everything back (and I did it wrong), and the camera area focusing light could not even lit. Ended up had to take the camera to a qualified camera professional to repair.
_________________
Zeiss: CJZ Flektogon 20/2.8, CJZ Flektogon 20/4, , CJZ Pentacon 29/2.8, CJZ Flektogon 35/2.4, CJZ Pancolar 50/1.8, Tessar 50/2.8, Biotar 7.5cm/1.5, CJZ Pancolar 80/1.8, CJZ Sonnar 135/3.5, CJZ Pentacon 135/2.8 CJZ Sonnar 200/2.8
Other Germany: Meyer Primoplan 50/1.8, Meyer Trioplan 100/2.8
Takumar: SMC 50/1.4 Super Tak 55/2, Super Tak 85/1.9, S-M-C 135/3.5, Super Tak 150/4
Russian: Zenith 16/2.8, Mir-24M 2/35, Volna-9 50/2.8, Helios 44M (58/2), Helios 44M-3 MC (58/2), Helios 40 (85/1.5), Tair 11A (135/2.8 )
Others: Sears 28/2.8, Sankor 35/2.8, Enna M�nchen Tele-Ennalyt 135/3.5
Zoom Sigma Zoom 28-85/3.5-4.5
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naplam
Joined: 22 Mar 2007
Posts: 469
Location: Spain
Expire: 2013-11-30
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| Posted: Thu Apr 23, 2009 10:35 am Post subject: |
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naplam wrote:
| rawhead wrote: |
| So, believe me when I say, you WILL know if the shim is not there |
Ok, i was just guessing. |
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naplam
Joined: 22 Mar 2007
Posts: 469
Location: Spain
Expire: 2013-11-30
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| Posted: Thu Apr 23, 2009 10:59 am Post subject: |
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naplam wrote:
| my_photography wrote: |
| Any way, I tried to put everything back (and I did it wrong), and the camera area focusing light could not even lit. Ended up had to take the camera to a qualified camera professional to repair |
I had had my focus screen quite dirty for a long time, I refused to clean it just in case i could screw up, I feared i could end up having to repair something. Only when I got the split prism screen I took the risk. |
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