Split screen focusing

[mikkokam]

I finally got a split screen for focusing. It has a twin split in 45 degree angle + microprism around it. Installation was easy although no instructions were included with the item. The package had two shims for calibrating the distance from the prism + two tweezers to help the installation. I managed to install the screen upside down first - resulting in a major front focus.

The website was of little help, but I found advice on other sites of similar products. Calibrated the screen with the shims using a ruler as a test target.

The results are great. The Sony (A100) body focus confirmation seems to be a bit off, which had driven me crazy when shooting at f/1.4 or trying to shoot very shallow DoF macro like this one:


Comparison / camera electronics (left) vs. eye & split screen:



Best of all, the screen was 14 EUR (eBay, from China) so I think it was well worth the price...
Ended up installing a magnifier eye cup as well - MF is now almost as good as it was with a film SLR some 20 years ago.
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Latest pictures: http://www.flickr.com/mikkokam
Lenses: Vivitar 17/3.5 • Vivitar Series 1 28/1.9 • Carl Zeiss Jena Flektogon 35/2.4 • Yashinon DS-M 50/1.4 • Helios 44-3 MC 58/2 • Helios 44M-4 58/2 • Helios 40-2 85/1.5 • Carl Zeiss Jena Sonnar 135/3.5 • Jupiter-37A 135/3.5 • DIY toy lenses 170/2.8 & 85/1.4 • DIY soft focus 50/1.8 • DIY tilt-shift lenses 75/3.5 & 75/4.5

[poilu]

congrats! a calibrated screen is important to enjoy manual focus
many doesn't succeed and go back to AF

[Nima]

MikkoKam,

I did the same recently. I purchased a K3 split screen from focusingscreen.com and also bought a magnifier cup for my Samsung GX20.

How did you fine tune the focus? What procedure did you follow? Can you give some pointers?

Thanks,
Nima

[mikkokam]

Hi Nima, these are steps that could help.
Anyone else with more experience, please correct me if I am wrong.

1/ SANITY CHECK:
The split screen showed the focus to be OK, but the pictures came out with something else (in front of the focus point) being in focus. The symptom was very clear, the focus was way off.
I had installed the screen upside down first - thus there was a bad front focus. Reversed the screen, and it was close, but not quite there.

2/ FINETUNING - CHECK:
Laid a ruler longitudinally on a table (at a distance within focus range of a few lenses / more than 1/2 meter away) and put the camera on the tripod. Focused very carefully at the middle line of the ruler, at 15 cm. To exclude error in focusing took 2-3 shots, refocusing each time. Reviewed the pics on the laptop screen. The line actually getting the best focus was now a bit BEHIND the 15 cm line. This means you need to add something under the focus screen.

3/ ADJUST:
The screen came with 2 shims (thin plastic cut into form of a frame).
I detached the focus screen and put a single shim under the screen to start with. That is, take out the focus screen, and add a shim, then the screen, then the metal clip holding the screen.
Rechecked. Now it was excellent - I was able to get +/- 1 mm accuracy from 1/2 meter, and the error in the test shots were on both sides of the 15 cm mark, so it was now calibrated.
Had it been still back, I would've added the other shim.

If you don't have the pre-cut plastic shims: some people have used very tiny pieces cut from a Post-it, placing them under the focus screen one-by-one, on the edges of it.

4/ DOUBLE CHECK:
Just in case, I checked the calibration with a few of my MF lenses, with different focal lengths as well. All was well.

5/ FRONT FOCUS:
If you focus on a mark and the actual focus in the picture turns out to be in front of it, you need to first check the sanity check (screen upside down = a lot of front focus).
If it is a slight front focus, then you should be able to remove something under the focus screen. I remember seeing a blog where a person removed the copper shim that is the bottom-most loose piece there.

Apparently some focus screens actually rely on you to remove it, while mine did not (for example, the Haoda screen is thicker than my focus screen is).
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Latest pictures: http://www.flickr.com/mikkokam
Lenses: Vivitar 17/3.5 • Vivitar Series 1 28/1.9 • Carl Zeiss Jena Flektogon 35/2.4 • Yashinon DS-M 50/1.4 • Helios 44-3 MC 58/2 • Helios 44M-4 58/2 • Helios 40-2 85/1.5 • Carl Zeiss Jena Sonnar 135/3.5 • Jupiter-37A 135/3.5 • DIY toy lenses 170/2.8 & 85/1.4 • DIY soft focus 50/1.8 • DIY tilt-shift lenses 75/3.5 & 75/4.5

[martinsmith99]

I have a focus screen from jinfinance that I never use as I can get better focus with my Canon EF-S screen.

I'm not sure if it's the fault of the screen or the user, but I can never get portraits in focus (or even close) with the split image screen. I'll give the ruler test a go.
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[Big Dawg]

Need to get one for my K10D. Focus confirmation works fairly well with mine until I try getting a truly sharp Macro with my Vivitar series one 105mm macro lens or a sharp detail photo from 30-40 feet distance with my Bigma. I know it is a tad front focusing right now and my eyes are not good enough to correct it. Thus the split screen (properly calibrated) would be a great aid to better focus.
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Big Dawg

[greg]

Don't forget to set the diopter setting each time you adjust or replace the screen. With no lens, adjust the diopter to make the screen in focus.
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Various DSLR bodies and MF lenses

[greg]

mikkokam,

I forgot to ask, what is the seller's eBay ID ?

Thanks, Greg
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Various DSLR bodies and MF lenses

[mikkokam]

The split screen was a double-split at 45 degree + microprism from "phopix88" (New Split Image Focusing Screen for Sony A100/A200).

The magnifier was a Tenpa, from "square-man" at eBay.

BR,
Mikko
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Latest pictures: http://www.flickr.com/mikkokam
Lenses: Vivitar 17/3.5 • Vivitar Series 1 28/1.9 • Carl Zeiss Jena Flektogon 35/2.4 • Yashinon DS-M 50/1.4 • Helios 44-3 MC 58/2 • Helios 44M-4 58/2 • Helios 40-2 85/1.5 • Carl Zeiss Jena Sonnar 135/3.5 • Jupiter-37A 135/3.5 • DIY toy lenses 170/2.8 & 85/1.4 • DIY soft focus 50/1.8 • DIY tilt-shift lenses 75/3.5 & 75/4.5

[martinsmith99]

[Séamuis]

I just purchased a screen from focusingscreen.com for my istD. I hope I do not have to shim it for accurate focus.
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Fish-Eye -- Fish-Eye-Takumar 1:11/18
WideAngle -- Super-Takumar 1:3.5/28, Auto-Takumar 1:2.3/35, Auto-Takumar 1:3.5/35, Super-Takumar 1:3.5/35
Normal -- S-M-C Takumar 1:1.4/50, Auto-Takumar 1:1.8/55, Super-Takumar 1:1.8/55, S-M-C Takumar 1:1.8/55, SMC Takumar 1:1.8/55, Auto-Takumar 1:2/55
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Medium Format -- S-M-C Takumar 6X7 1:2.8/90 LS
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[Blue]

For a couple of months I have been wondering if there is an advantage to the double split compared to a single split screen. I normally don't think of a split screen as helpful in macro work. Conceptually, I think the double may be. I have watched those double 45 degree screens on ebay for some time.
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Rangefinders: Argus C4 and Ricoh Five-One-Nine

[mikkokam]

When not in focus, the double split breaks a section of a line and moves it off. Sometimes it may be easier to align it then. I doubt if there is a major difference, though.

Mine is set at a 45 degree angle. For fine-tuning the focus, this is both good and bad. The good is, it is easy to tilt the camera just a bit for both horizontal and vertical lines, whichever is available at the focus distance. The bad is, you end up always tilting: There is rarely a line that would be at the correct angle (more specifically, at a 90 degree angle to the split).

Of course, you do not need to tilt to get it roughly right quickly, horizontal and vertical lines can be used like this:

_________________
Latest pictures: http://www.flickr.com/mikkokam
Lenses: Vivitar 17/3.5 • Vivitar Series 1 28/1.9 • Carl Zeiss Jena Flektogon 35/2.4 • Yashinon DS-M 50/1.4 • Helios 44-3 MC 58/2 • Helios 44M-4 58/2 • Helios 40-2 85/1.5 • Carl Zeiss Jena Sonnar 135/3.5 • Jupiter-37A 135/3.5 • DIY toy lenses 170/2.8 & 85/1.4 • DIY soft focus 50/1.8 • DIY tilt-shift lenses 75/3.5 & 75/4.5

[Blue]

That last image is encouragement to give one a try on my K200d. If it works out, I may get one for the K20d later. What got my attention is the area between the 2 diagonal splits.
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Pentax: K, H2, H3, SV, SV black, Spot F, K2, ME F, SuperProgram, 6x7, Auto 110
Pentax "modern": MZ-3, K200d, K20d
Mamiya: C3 TLR, NC1000
Canon: EOS 10s, AE-1
Chinon: CP-7m
Praktiflex FX & Victar 50mm f2.9
Contessa-Nettel Piccolette - 7.5 cm Tessar & Compur shutter
Rangefinders: Argus C4 and Ricoh Five-One-Nine

[Jekku]

I'm having problems with my split focus screen, It focuses to short distances superb but if I try shoot something that's about 2.5ft/0,8m away everything is a mess. Blurry as bokeh so to speak.

What should I do?

I've tested, retested and retested the retest. Removed the shim etc.
Have messed up the screen?
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