[3dreal]

Hello my story is a bit complicated. but i know what i do and i have already done a lot to find out if and by how much my new 200/4 67 lens and old 135/2.8 6x7 lens are deadjusted. will further check with Canon EF and Nikon-adapters. Problem No 1. i dont have 67 body.
there is a reason. and problem No2: I am currently testing new P67-P6.adapter here use on kiev 60.
do no want to go into much details but i could. i could check with 2.cam-method if infinity is reached.
I suspect 200mm not getting infinity by very little. distance 7.7km, 135mm seems further off.

Problem 3: i suspect K+F concept-adapter is off by a little. since when switching adapters from EOS EF to Nikkor distance must be corrected.

Problem 4: new adapter is off by at least 2mm. I did measurements no1 and these 2mm are confirmed by my last chec
kings comparing mounts. cannot at the moment tell you how the adapter is made or how its looking. there are many option see pentaconsix dot com updates.
i learnt that digital caliper is not that precise than analogue ones. have two different kind of but not the same desing. dont know its naming.
even comparing the mount is telling me new adapter is 2mm too long.

have these data: On Kiev 60: these distances can be reached-at infinity: 200mm: 15.5m 135: 10.5m
one can calculate or measue ob helicoid by how much extension must be reduced to get infinity. at over 3mm. around 3.6mm
reducing register-difference from 3.6mm means 3.6-2= 1,6mm deviation on lens.
How is calculation done?
what is max. distance when helicoid is 1.6mm too long.
which is formula?
I used new brightscreen 679 univesal Groundglass matte/fresnel. customcut from 4x5 matte/fresnel-type

[photoptimist]

If the flange focal distance (lens-mount to film-plane distance) is off by ∆, then the image magnification when the lens is supposedly at ∞ will be m = ∆/f. The distance from the film plane l to the focus point on the subject would be f*(2 + m + 1/m).

For ∆ = 2 mm, I'd expect the 135 mm lens to focus at about 9.4 meters and the 200 mm lens to focus at about 20.4 meters.

For ∆ = 2.6 mm, I'd expect the 135 mm lens to focus at about 7.3 meters and the 200 mm lens to focus at about 15.8 meters.

So maybe the adapter is off by 2mm and the 200mm lens is off by an additional 0.6mm


Some complicating issues:

1. The exact distance of adjustment of the helicoid is not easy to calculate because it is a function of the lens design. With some true telephoto lens designs (used to make the lens and helicoid more compact), the helicoid moves less than would be expected compared to the thin lens formula.

2. It is really hard to judge the center of focus near infinity because the hyper-focal effect biases the depth of field toward infinity. Although some use a one-third / two-thirds split between the front and back depth of field that is only correct if the center of focus is exactly one half the hyper-focal distance. If the lens is set to the hyperfocal distance then everything from 1/2 the hyperfocal distance to infinity is "in focus." Compounding this issue is that atmospheric disturbances and haze make distant objects fuzzier than they should be. Stars at the zenith make a good "infinity" target but unless the lens can focus past infinity, it's hard to tell whether the non-zero size of the stars is caused by atmospheric effects, aberrations in the lens, or a lens that cannot get to infinity focus.


Overall, it seems the adaptor is certainly damaged, defective, designed wrong. It's also possible that the camera body is not quite right, either.

[UncleVanya]

That much error in adapter length is unheard of. Typically the error is the other way and very very small. Most adapters are intentionally made slightly shorter than it’s “correct” To ensure that users can reach infinity. This is one reason that the corners of wide angle shots using adapted lenses on mirrorless cameras can be really soft unless the adapter is very precise.

[kaseki]

One really needs such as a Nikon autocollimator on an optical bench to establish an atmospheric turbulence free 'infinity' projection for determining what the camera/lens is actually doing. As these are pricey, rental or lab testing may be more affordable. Otherwise, one might use Jupiter or the Moon as a subject on a still night where the local atmospheric temperature is nearly that of the ground. Even under these conditions, point sources such as stars will always blur and dance around in any near sea level atmosphere, less so at the top of Mauna Kea and similar altitudes.

[3dreal]

we me and rafcamera.see other new thread by me are coming near to the truth. 1. i must first have a feelling of perfect sharpness at 7.7km little church and 200m tv-tower. no i will not judge the needle but the house up there about the same size like the chapel. will show when i have best possible sharpness using perfect zeiss 200/3.5 scale checked. and other lenses and system. one is for both MF and FF/APS-.C with changing heads. old novoflex A-tube focus-fotsniper design. can go beyond infinity. p6-bellows attached. can also shoot with novoflex B and c-systems 400/5.6 triplet very sharp and 600/8 less sharp. perfect wheather here after rain, only have now sunset images. also dont know if its jpg-unsharpness have raw. no deadjusted rafcamera adapter used but K+F comfort. where is suspect nikon-version is not precise. other one: EF-EOS. will get newest Novoflex Nikon-combo P67-system. to nail the mistakes. will also test all my other FF -adapters. newest pixco ni-EF. have K+F comfort best for C/Y-EF. yes i found difference to others. the mentiones aps-c-shots not done with special P67-M68(P6)-adapter but K+F comfort.
measuring the adapter and calculating deviation i come to 1.12mm between needed register and measured adapter. that is really true since adapter cannot be mounted full 2 1/4 rotation., its going in only mayb 350. difference 1.mm!!! means when he changes that infinity may be reached with perfect lens.
helicoid is telling: 15.5m to infinity 3.5mm. 3.5 -1.12= 2.38mm.
dont know what is meant with the triangle. pls let me know. if 200m helicoid is moved from infinity by 2.38mm which distance is reached? pls add calculation.
read also my finding in new thread about rafcamera adapter. he also make one for macro 0.2-1m and biometar 120/2.8 for P67.
NB: with deadjusted adapter it is easily possible to judge defocussed P67 lenses on P6-camera.one will get near distances and target easier to judge., e.g. at 15,5m outside i have tiny Siemens letters. and when dark enough i can check distance with bosch zamo HQ-lasermeter only when EV is 7 and darker.

---------- Post added 09-25-22 at 08:24 PM ----------

If the flange focal distance (lens-mount to film-plane distance) is off by ∆, then the image magnification when the lens is supposedly at ∞ will be m = ∆/f. The distance from the film plane l to the focus point on the subject would be f*(2 + m + 1/m).

For ∆ = 2 mm, I'd expect the 135 mm lens to focus at about 9.4 meters and the 200 mm lens to focus at about 20.4 meters.

For ∆ = 2.6 mm, I'd expect the 135 mm lens to focus at about 7.3 meters and the 200 mm lens to focus at about 15.8 meters.

So maybe the adapter is off by 2mm and the 200mm lens is off by an additional 0.6mm


Some complicating issues:

1. The exact distance of adjustment of the helicoid is not easy to calculate because it is a function of the lens design. With some true telephoto lens designs (used to make the lens and helicoid more compact), the helicoid moves less than would be expected compared to the thin lens formula.

2. It is really hard to judge the center of focus near infinity because the hyper-focal effect biases the depth of field toward infinity. Although some use a one-third / two-thirds split between the front and back depth of field that is only correct if the center of focus is exactly one half the hyper-focal distance. If the lens is set to the hyperfocal distance then everything from 1/2 the hyperfocal distance to infinity is "in focus." Compounding this issue is that atmospheric disturbances and haze make distant objects fuzzier than they should be. Stars at the zenith make a good "infinity" target but unless the lens can focus past infinity, it's hard to tell whether the non-zero size of the stars is caused by atmospheric effects, aberrations in the lens, or a lens that cannot get to infinity focus.


Overall, it seems the adaptor is certainly damaged, defective, designed wrong. It's also possible that the camera body is not quite right, either.

i thought 135mm is more deadjusted.it not easy judging since 7.7km is too far.
will judge a nearer distance and tell helicoid difference 10.5 to infinity. maybe possible infinity-judging by comparing 135mm lenses. i also have very sharp MUP 150 blue(not better than standard only different shape of one blade-bent blade) and vacuum-back can even use 220 beside 70mm. can use technical pan. but then must shoot also with Kiev 60 or best would be p67 with vacuum-mag.orHBV conversion with vacuum mag.

---------- Post added 09-25-22 at 08:43 PM ----------

when judging from lens-helicoid-difference 3.5mm minus 1.12 too thick adapter= 2.38mm lens-deviation i am getting 86m. but can only judge when having perfect p67-lens.
can judge p67 lenses on K+F comfort but need sharp target at 100m. i can calculate with gps-map-ruler. thats what i used to measure distances in town.
i will find such a target. maybe best waiting for Novoflex-P67 universal adapter 300 euro complete. sooner or later will also get nikon DSRL D5200.

[yucatanPentax]

A European football field is generally between 100m and ~120m long. If looking for an exacting distance, that might work. They are relatively easy to find.

[MossyRocks]

My general approach for testing for infinity is to get out a heavy tripod and focus in magnified live view on a bright star centered in the frame while wide open. Be sure to have focus peaking turned off. I like my lenses to go slightly beyond infinity and it becomes apparent if the lens goes slightly beyond infinity as you will see the star shrink, become as small as it is going to get, and then get slightly bigger. I know over in the astro group there was someone who was using a lens with an adapter that was a bit too thick and my suggest there was to shave down the adapter on the lens facing side (it was just a mechanical adapter no control or electronics) and that worked.

[3dreal]

no free access- but good tip. filmflatness is also a big issue no matter what people are telling. tiny little differences and perfect sharpness gone. have seen enoug unsharp hasselbla prints. had been fighting against that enemy for over 50 years and its no ending. one can verify about that in rotapancams.net login needed. my forum about crappy rotapancameras from SU and JP.
saw unsharp results in linhof magazine. better forgetting tomyiama artpanorama 612. wrong design. repairman could hardly imprive fillmflatness.
but here its about a totally different problem. or problems. more could come when is start shooting on film. but only center will be verified.
will now measure 200mm situation with eos-adapter then Nikon-version. checking register. i suspect K+F comfort Nikon-P67 is deadjusted. will get the perfect new Novoflex adapter system starting with Nikon. easy to nail the deviations.
https://www.novoflex.de/de/produkte/adapter/adapterfinder/adapterfinder-prod...-pentax-k.html sorry not the right link but from here one could imagine altering this PK-adapter to have both outer and inner-mount by P67-lenses see pentaconsix dot com discussion. we are discussing also K+F comfort pendant i have it here. altering PK-side should be easy adding M68,
no need to show images. if i nail distance with 200mm or 135mm and image is not sharp anymore when switching from eos to ni there is an adapter problem distance approx. 18m
can also test 50, 60, 70m or 100m here.

---------- Post added 09-26-22 at 08:44 AM ----------

yes star and idea but not with rafcamera-adapter not made for other than M68. how about using the focus-filter? forgot its name.
yes where i was testing is an observatory nearby so good location just outside town on other side. deep dark sky.
yes i didnt use yet tripod. cam was lying on a sort of decubitus-pillow. but long exposure of nearby sharp images-houses perfects. so pillow a good tripod.also for 7.7km. but i wasnt there yet at more bright day. sky clean. last sunrays. next is shooting at town. easy to carry tripod. i have damages right hand. but i can take trolley and assistant then. it seems the adapter is really 1.72mm of or 1.12mm i suspect 0.6 difference for digital caliper. too long. dont yet have identical mechanical one but for thickness. further comparing to verify possible deviation. i am now discussing how actual adapter must be changed. maybe thread too short. etc. when i have more details i can report. must know experts opinion. rafcamera.

[3dreal]

Problem at far distances is: can i check focus? i did not more testings also comparing on special nikon-HBV camera. here are the results:
closeups 1.5m
M68 - 200mm: 1.42m 135mm: 1.367m
Nikon . 200mm: 1.48m 135mm: 1.42m same like 200mm on special P6-mount.
both max(at infinity) and closest distances
135mm M 68: 10.5 -1.367m (Inf-1.5m on scale)
Nikon: ? -1.42m will also test infinity. same with eos-adapter. registerdifference 1mm or less too long nonreaching infinity.
200mm: M68: 15.5 -1.42m (infinity-1.5m on scale)
Nikon: ? - 1.48m thinner difference than 135mm maybe 0.6m which someone suggested.
EOS will also be retested. K+F comfort adapters.
will get asap Novoflex special universal P67-adapter-Nikon mount first. will also check if there are differences comparing direct EOS with Ni-EOS-adapter.
on groundglass with fresnel not easy focussing if target is not big enough. will enlarge and get better loupe 20x or 30x.
brightscreen is plastic so any push will change focus. try to use other nontouch loupe.
manfrotto macroslider 454 is fantastic. clever design. two knobs and quick move lever.-
Bosch Zamo III(attachements! ) laser most perfect. dont use cheap ones they are not correct.

[ProfessorBuzz]

Test it out on the stars on a still night. If the body has Live View, that's a good way to have a look.
Don't use a planet - they are too bright and large.

[3dreal]

200mn is only a bit off. maybe really the mentioned 0.6mm.want now know how far it will go with 0.6mm less extension. then calculating needed reduction to infinity.

[3dreal]

will now check indirectly by using eos-digital camera by how much extension on adapter must be reduced to get infinity. see other thread about rafcamera adapter. this too long adapter is the ideal choice(one can also use his macro-adapter for real P6.mount) to verify lenses-infinty.
we found out that 200mm new is about 0.6mm deadjusted. its not much. we will see when taking new shots.
i will then calculate distance which is reached -longer than actual 15,.5m with p6-adapter. calculation done 0.6mm shorter extension used. maybe you could help already. i could then find an ideal target to verify. have a large clock used for other tests on film. 430m away. this time it will be nearer. hard to judge sharpness on camera with longer distances. if lens is only 200mm. i will also simulate with other 200mm. e.g, zeiss/c/y which should get very sharp images..

[3dreal]

latest test was comparing 200mm p67 new with novoflex noflexar 200/3.8 at best aperture f8(f11 also ok at infinity). the latter with ni-eos-adapter but going beyond infinity. and now its clear. P67 200/4 on K+F comfort-Eos doesnt reach infinity. when i had p67-Zeiss c/y compared they showed indentically sharp/unsharp. means also Zeiss is not reaching infinity. that is clear after latest shooting.
will now do further testings since its not yet clear if adapters are perfect. 2cam-test could be an option.

[3dreal]

it seems we have found out. analoge lenses are calibrated for IR-sensitive film which isnt the case for digitalcamera-sensors. except if lenses go beyond like Noflexar 200/3.8 novoflex newest followfocus lens. can exchange and combine many adapters for EOS-60D- APS-C-18MP use.
thats why novoflex P67-adapter system is going slightly beyond infinity. so are the P67-M68(P6 and Kiev60 versions) Rafcamera-adapters.
strange thing is Zeiss C/Y 200/3.5 AE on K+F comfort EOS -adapter is shifting towards 1.5m at 2m. on Contax-camera 2m are nailed.
means this adapter i shorter must reach infinity. which is not the case. infinity at 7.8km slightly unsharp. same result with also K+F comfort P67-eos-adapter..
they must make the adapters shorter.
will make more testings this time with tripod.
NB: best aperture at infinity are f8(two stops) and f11. middle distances also f16. P67 200mm meant. didnt test old 135/2.8 for infinity yet.
---------- Post added 10-22-22 at 02:58 AM ----------

[3dreal]

Have great news and progress. i made and adjustable P67-Nikon-adapter by combining two parts. it only needs thread to tighten them.
here are the results also real registers of K+F comfort nikon and eos -adapters:
1. K+F comfort Nikon: 85.6 must be 84.95, difference + 0.65 too long. analoge vernier caliper tested.
EOS: 85.75 = +0.8mm too long.

2. adjustable Nikon-adapter has now minus 0.28mm register.
200mm and 135 clearly should go beyond infinity. i hope.-
135/2.8 old at 2m showing 1.8m,
helicoid difference on both the same: 1.5mm.
when compensating the 0.28. if i would make it just 84.95mm difference is 1.22mm.means adapter should be 1.22mm shorter.
can someone calculate helicoid-difference using these 2 and 1,8m values.