NikonGear'23
Gear Talk => What the Nerds Do => Topic started by: FGAng on September 12, 2016, 04:18:13
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I have some questions, but first the background.
Yesterday I succumbed by my NAS and bought a silver 45mm f/2.8 AiP. The pricing was 200 EUR, and as seller hadn't use the lens for the past few months, he checked it and found out the aperture was sluggish, in his words, beyond f/8. With that known issue, I got him to sell it to me at 150 EUR. Prices equivalent from Singapore dollars.
Sure enough I tested it there was some sluggishness in the aperture, and initial shooting at f/16 yielded about 1.3 stops of overexposure. Brought it home, exercised the diaphragm, and this morning I tested the aperture to close down "correctly" at f/11, and at f/16 the value was about between 2/3 and 1 stop out (closing to 1 stop). Unscientific test, using the lens on a Df and shooting a scene outside my window, cycling through the apertures from f/2.8 through f/16. Significant vignette at f/2.8, improving by f/4, gone by f/5.6. Consistent histogram from f/5.6 through f/11, and at f/16 to shifted to the right, determined to be between 2/3 and 1 stop by shooting at f/8 and using exposure compensation and watching the histogram. Weather condition remained relatively constant - overcast, which is good, as there would be little change of lighting.
My question:
- could this issue be due to storage of lens at its widest aperture, hence putting the spring at tension in storage?
- subjectively, if I now store the lens at the minimum aperture, and exercise the lens (use the lens) regularly, would I be able to get the aperture back to (or close to its original performance specification?
I have tested and am satisfied that up to f/11 there is no problem. And should be able to work around the f/16 issue if needed (like shoot manual exposure with lens stopped down).
Thanks.
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My answer:
- No.
- No.
There must be either some oil or grease in the aperture somewhere, bad return spring or the aperture leaver is bent out of shape.
So, lens not on the camera, feel with your the tip of your finger how the operation feels like when operating the leaver at smallest aperture, compare it to other lenses.
Shoot a couple of images close up of the aperture blades and the leaver.
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yes, oily aperture definitely.
i flick the lever in rapid succession and you should see some inconsistencies.
look at the front or back side, see if there is shiny or dark marks on the blade.
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Lubrication seeping onto the aperture blades is a troublesome matter unless the lens is properly and professionally cleaned to get rid of it. I sincerely doubt whether the lens being used or not has much influence once the damage has been inflicted.
Unless repaired, one can never really trust the lens in operation. Sometimes it might work well, sometimes the aperture seizes up and you get gross overexposure. The 55/2.8 Micro-Nikkor was infamous for this issue and my first copy was cleaned twice before I gave it up and just dumped it into the waste bin. A second copy bought many moons later is just fine, though.
I have had several copies of the 45/2.8 Ai-P without any aperture issue, thus apparently this problem is not applicable to the whole production run. My current black 45P has perfect aperture functionality.
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Thanks to Erick, Rick and Bjorn for your replies.
Some photos to see if some diagnosis can be arrived at:
First the lever
(http://gallery.clubsnap.com/data/500/medium/160912_063_45f2_8_AiP.jpg)
(http://gallery.clubsnap.com/data/500/medium/160912_064_45f2_8_AiP.jpg)
(http://gallery.clubsnap.com/data/500/medium/160912_065_45f2_8_AiP.jpg)
The the blades.
From rear
(http://gallery.clubsnap.com/data/500/medium/160912_070_45f2_8_AiP.jpg)
From front
(http://gallery.clubsnap.com/data/500/medium/160912_074_45f2_8_AiP.jpg)
Thank you once again. I am resisting the urge to dismantle the lens... trying to be not OCD (disassembler).
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Leaver and blades look pristine.
Could be the return spring or,,, the camera
What are those specs around the edge of the blades?
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Thanks Erick, the specs are simply dust at the front baffle - nearly 1:1 on a D300, so greatly magnified (nearly 1.5:1).
Unlikely to be camera, since the situation was detected by the seller using a different body, confirmed to be so with my Df.
I did what Rick told me, last night, and today, and the aperture appear to return more snappy than when it first arrived. My thoughts are that it is likely the spring (that's what I felt from the beginning anyway), since the blades look pristine and clean to me as well.
Maybe I will need to cannibalize from a piece of junk in Rick's pile to replace the spring... :).
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Agree with Erik. No signs of oil seepage in the lens or any issue with the aperture stop-down lever. Thus one has to look elsewhere. A badly tensioned return spring should be detectable if you set the aperture on the lens to the smallest value (lens off camera), push the stop-down lever to open the aperture, then release it; the blades should stop down immediately without any delay. Do this repeatedly to check that stopping down is consistent. If the aperture responds sluggish on occasion, the return spring is the major candidate. I doubt there is true oil leakage when the actual leaves are this pristine (ref. your photo).
The final check is with the camera. First, set up the camera to use aperture ring on lens to control the aperture, then stop down the lens to f/22. Find a bright subject, mount camera on a tripod and put the camera to the fastest possible frame rate in continuous release mode (you might use jpgs for this as they are just test dummies). Fire away, then make an overview of the jpgs to see they are evenly exposed. If they OK, do a second series in which you change to make aperture selection on camera instead, then dial in f/22 and repeat. If the jpgs now are unevenly exposed (and the first series is OK), the problem is the stop-down lever in the camera.
Obviously, if the first series as described above produces uneven exposures, the lens needs to be serviced. Replacing a worn tension spring should be a quick and easy fix with any camera repair shop worthy of the description.
.... - nearly 1:1 on a D300, so greatly magnified (nearly 1.5:1)....
An assumption often made, but still entirely wrong. Magnification is a scaling property, thus the format does not change the ratio number at all. Life-size 1:1 is the same on any format. What changes is the field of coverage. It can go from encompassing a match head on a CX camera to a full facial portrait on 8x10". What does not change is the exposure compensation required and the depth of field as both are influenced by the actual magnification.
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Thank Bjorn. This morning I ran 2 series of test on my Df, 10 and 11 frames, at CH. Hand held, shooting out of the window of my flat.
First series, 1st shot
(http://gallery.clubsnap.com/data/500/medium/160912_014_45f2_8_AiP_f16_burst.jpg)
6th shot
(http://gallery.clubsnap.com/data/500/medium/160912_019_45f2_8_AiP_f16_burst.jpg)
10th shot
(http://gallery.clubsnap.com/data/500/medium/160912_023_45f2_8_AiP_f16_burst.jpg)
Not sure if it is a little hard to see on the screen, there is some over exposure on the first 3 or so shots, then the exposure was more even, but not very even.
Similar results from the second series.
I am actually quite inclined to leave it as it is, at least for now, until such time I find a reason to open up this lens and replace the spring from a cannibalized lens...
Thanks Bjorn.
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Thank Bjorn, I understand the math that 1:1 is 1:1 is 1:1 whatever the format. What I was saying is that at 1:1 I get a 50% larger image ... on screen or on print.. :). But, you are correct.
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50% wider coverage (at 1:1) is different from 1.5X magnification.
This stuff was so obvious back in the old days when we shot with different film-based formats. For example, on my 6x9 cm camera I might need a panoramic coverage so just put the 6x12 or 6x17 back on it whilst keeping the lens (if it had adequate cover, but most had since I regularly used 4x5" lenses on the smaller camera). One didn't need refocusing, altering exposure, or anything, but just got a broader view. Of course details on film kept their exact same size as I had just extended the format not altered magnification.
These days most of this is downed in the tsunami of "equivalence" and "crop factor" nonsense. Nobody cares because they have read the 'truth' - on the internet.
Rant mode off.
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I fail to see any difference in those three exposures at all,,,
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Thanks Erick. That confirms my inclination, of not meddling with the lens and live within the minor issue.
There is a difference - when seeing the histogram - the first one is further to the right, and shot at 5.5 fps, the lighting should not be the issue... but remember these are all f/16 shooting in rapid burst.
And when I shot from f/2.8 cycling through to f/16, change is pronounce between f/11 and f/16. Anyway the problem has decreased after I shot it repeatedly for 50 or so shots.
This was the first f/16 shot after leaving the seller's place, clearly over exposed, due to the sluggish aperture blades closing.:
(http://gallery.clubsnap.com/data/500/medium/160911_010_45f2_8_AiP.jpg)
And thanks for all your help. I am quite sure the spring has a little problem. One day I will open it up and replace the spring with a cannibalized spring and try again!
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There is a ball race in manual focus lenses that must remain dry, unlubricated. The stop down lever in the lens runs on this ball race. The lever must run very fast to stop down to minimum aperture and to keep up with a motor drive. I wonder if those ball bearings could have a tiny bit of oil on them that separated from the grease. That's probably unlikely. I don't see lube contamination of the aperture blades. It could be just starting.
I'll bet there is something impeding the aperture stop down lever in the lens just a bit.
If the camera is set manual exposure and there is no change in the exposure settings is the problem still seen? If so I'd have the lens serviced.
Dave
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...
This was the first f/16 shot after leaving the seller's place, clearly over exposed, due to the sluggish aperture blades closing.:
..
IMHO this is not very serious,,, :o :o :o Shot though a car window,,, ?
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There is a ball race in manual focus lenses that must remain dry, unlubricated. The stop down lever in the lens runs on this ball race. The lever must run very fast to stop down to minimum aperture and to keep up with a motor drive. I wonder if those ball bearings could have a tiny bit of oil on them that separated from the grease. That's probably unlikely. I don't see lube contamination of the aperture blades. It could be just starting.
I'll bet there is something impeding the aperture stop down lever in the lens just a bit.
If the camera is set manual exposure and there is no change in the exposure settings is the problem still seen? If so I'd have the lens serviced.
Dave
Are you sure this has a ball race? Normally only old lenses, and long build length has this,,,,
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this is weird. the lens has to be opened :o :o :o
it is possible that the bearings have gummed up but i have not seen anything like this even in the worst of the junk nikkos that I have worked with. but since this is a cosina-made lens then the engineering might be different. ::)
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The 45P is made by Cosina?
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The 45P is made by Cosina?
Yes :o :o :o
I also suspect the 45mm f/2.8 GN as well because the engineering techniques used are VERY different from what Nikon uses and the choice of hood type is much more in line with cosina. here in Japan, when a company wants to make a product that is cheap but cannot produce it cheap enough themselves then they would outsource it elsewhere - in this case, Nikon to Cosina. some would even claim that some of the Series E lenses were subcontracted as well but i cannot confirm that. ::)
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I can't say I've seen a ball race in a Nikkor that was gummed up. I think I fought with one while reinstalling the meter coupling lever in a PK-11. A PK-11 soon modified can be used to install a pre-AI lens on current and recent dSLR(s) like 55/3.5 compensating aperture Micro-Nikkor. I wish I had it back and without the meter coupling.
Dave
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Hmmm, interesting. I always thought the 45P was made by Nikon. It is a unique lens - pity they didn't make more like it.
I have seen the Nikon branded AIS 35-70/3.5-4.8 and 70-210/4.5-5.6 which are made by Cosina. Apart from the rather "Series-E" type build, the giveaway is the number of aperture blades - 6 for the 35-70 and 8 for the 70-210 - which is not Nikon style at all. Nikon last used 6 aperture blades with the AI 50/2 and 55/3.5 micro until the late 1970s, and never made SLR lenses with 8 blades.
I'm not sure about the 45GN - this lens is very different by virtue of the GN mechanism, for example the focus ring turns the opposite way from other Nikkors and runs on a cam instead of a helix. Wouldn't that explain the different engineering? Or are there other differences - choice of materials, style of construction - which point to a different manufacturer? The hood is unique too, but even if it was made by a third party, surely it would be designed by Nikon. I don't have any hard evidence either way, but always assumed it was made by Nikon.
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I though 45P (as well as Series-E) was made by Tokina. :o :o :o
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I can't say I've seen a ball race in a Nikkor that was gummed up. I think I fought with one while reinstalling the meter coupling lever in a PK-11. A PK-11 soon modified can be used to install a pre-AI lens on current and recent dSLR(s) like 55/3.5 compensating aperture Micro-Nikkor. I wish I had it back and without the meter coupling.
Dave
i avoid opening these up if i can help it :o :o :o
they are a pain!
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Hmmm, interesting. I always thought the 45P was made by Nikon. It is a unique lens - pity they didn't make more like it.
I'm not sure about the 45GN - this lens is very different by virtue of the GN mechanism, for example the focus ring turns the opposite way from other Nikkors and runs on a cam instead of a helix. Wouldn't that explain the different engineering? Or are there other differences - choice of materials, style of construction - which point to a different manufacturer? The hood is unique too, but even if it was made by a third party, surely it would be designed by Nikon. I don't have any hard evidence either way, but always assumed it was made by Nikon.
https://richardhaw.com/2016/03/13/repair-gn-auto-nikkor-45mm-f2-8/
the use of a cam for focusing might be necessary because it has to turn at the same rte as the aperture ring :o :o :o also, the tooling used felt "alien". I am not sure, maybe I can confirm this one of these days when i meet Haruo Sato. :o :o :o
the 45P is special. I always wanted one but I still cannot find reasonably priced one or junk ::) the 45P felt like a chunky lens by the way. very dense. maybe mr Ang will open up his 45P soon and we will see what's inside ::)
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I though 45P (as well as Series-E) was made by Tokina. :o :o :o
no, Cosina :o :o :o
it seems that Cosina has a long history working with Nikon. Tokina on the other hand was setup by former Nikon engineers that were pissed off. ::)
http://page12.auctions.yahoo.co.jp/jp/auction/p508776400
this one is reasonably priced, but silver (I want black). too bad I cannot play the auctions now. had a conversation with my wife after getting the NOCT ::)
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https://richardhaw.com/2016/03/13/repair-gn-auto-nikkor-45mm-f2-8/
the use of a cam for focusing might be necessary because it has to turn at the same rte as the aperture ring :o :o :o also, the tooling used felt "alien". I am not sure, maybe I can confirm this one of these days when i meet Haruo Sato. :o :o :o
the 45P is special. I always wanted one but I still cannot find reasonably priced one or junk ::) the 45P felt like a chunky lens by the way. very dense. maybe mr Ang will open up his 45P soon and we will see what's inside ::)
As can be seen in the link the old 45mm GN doesn't have a ball-race or ball-bearing - It' actually looks more or less identical to most short Nikkor lenses in this regard.
The 45mm Ai-P,,, Balls,,, highly unlikely,,,
Cosina,,, urban legend so far :o :o :o
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There's one for sale in the "Classified Ads" section (shameful plug ;D)
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There's one for sale in the "Classified Ads" section (shameful plug ;D)
I have been thinking about it, i am not familiar with this lens, never tried one
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Thanks to so many responses, directly or indirectly.
Erik the shot was through a car window, does not appear too seriously over exposed.
Now a series of sunset shot out of the window (I am quite home bound after work). I think the problem is clear to see.
f/2.8
(http://gallery.clubsnap.com/data/500/medium/160913_077_45f2_8_AiP.jpg)
f/4
(http://gallery.clubsnap.com/data/500/medium/160913_078_45f2_8_AiP.jpg)
f/5.6
(http://gallery.clubsnap.com/data/500/medium/160913_079_45f2_8_AiP.jpg)
f/8
(http://gallery.clubsnap.com/data/500/medium/160913_080_45f2_8_AiP.jpg)
f/11
(http://gallery.clubsnap.com/data/500/medium/160913_081_45f2_8_AiP.jpg)
f/16
(http://gallery.clubsnap.com/data/500/medium/160913_082_45f2_8_AiP.jpg)
I quite like the OOF look (Bokeh?) of this lens. at f/2.8
(http://gallery.clubsnap.com/data/500/medium/160913_112_45f2_8_AiP.jpg)
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I have been thinking about it, i am not familiar with this lens, never tried one
Sharp, colourful, Voigtlander-like- works very good with close up lens and extenders. And lovely small. What more do you want ;)
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One needs to have small enough finger to operate it ... not *the* lens for winter photography with gloved hands, that's for sure (I have tried and gave it up).
Also a lens so small it goes easily AWOL. I quickly lost my first sample this way. Asked Nikon Nordic for a 50% refund on a new sample as I blamed the maker for selling such a small item -- and got it at discount price :D
The old GN 45 is a little easier to operate as it has a scalloped (though narrow) focusing ring, but due to its unusual construction the focusing itself is quite stiff and goes in the opposite direction of other Nikkors. I removed the linkage between aperture and focusing cam and now the lens is much smoother to operate, but its touted 'GN' feature is lost.
Th 'P' has modern coatings and thus gives somewhat better image contrast and colour fidelity if these properties are important to you. The old 'GN' is more mellow and rounded in its drawing.
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Yes I am overall very happy with the lens, even though at the moment I am reduced to shooting out of the window pretty much for another month...
But there is a clear trend that the lens isn't stopping down fast enough as the aperture gets smaller, resulting in increasing exposure. OK, f/2.8 and f/4 there is vignette. Right now the lens pretty much asked to be operated up to f/8, maybe f/11 max.
Someday I will cannibalize a spring, likely from a damage 35/2.5E, to see if this is the problem. But I hate opening up a new toy so soon after getting it... :(
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I bought a 45P with my FM3a over 10 years ago when they were still new. I never warmed to the 45P. I was hoping the bokeh would be smooth and nicely rounded, I found it to be rather clinical, not terrible but not what I was looking for. The lens is small, too small for me - I don't have large hands or need gloves in the NZ climate, but it was fiddly to operate - when turning the narrow aperture ring I would often touch the focus ring by mistake. Lack of solid real-estate on the barrel made it harder to grip when putting on and off the camera. The f/2.8 aperture also felt too slow for a standard lens. Maybe that's an odd thing to say, I used the 55/2.8 micro for years without complaining about the speed, and I rarely shoot at wider apertures, but I still felt I wanted more speed in a non-macro standard lens. I eventually sold it and switched to the AI 50/1.8 - this lens has much better ergonomics, is over a stop faster and the rendition, while not perfect is smooth enough for me. That was back in the days of film, I never used the 45P on a digital camera.
As for the 45GN, the later "C" multicoated version should give contrast and color fidelity nearly as good as the newer 45P. With only 6 glass-air surfaces the contrast should be high in any case, especially if the front lens is shaded from strong light.
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I am not confident of repairing this lens, so I went to my good friend David Hilos, and he quickly diagnosed the problem: oily blades. Oily blades could not be seen on the lens aperture, but when he disassembled the lens, oil is found at the periphery of the aperture mechanism!
(https://i1.wp.com/diediemustdive.files.wordpress.com/2017/03/170402_011_45f2-8-aip.jpg?ssl=1&w=450)
Cleaned up and it is now all good. Can't wait to get it back!
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I saw the same overexposure on 2 old lenses, also solved by cleaning the excess oil:
55mm f1.2, oil was outside the aperture assembly but was enough to gum things up
50mm f1.8 E series, excess oil all over the place, I'm surprised it didn't made it to the glass
It's to use them once cleaned, and to have consistent behavior
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just got one from the junk shop and overhauled it in and out last night, down to it's bare parts :o :o :o
the sluggish iris blades can come from 3 different causes:
- oil on iris (this lens very vulnerable)
- a bent iris lever/ring mechanism
- a bent C-ring on the inside of the objective's casing (very likely,too. I will show you why)
It is very unique and very unorthodox in terms of engineering. I learned a lot working with this lens.
the C-ring had to be implemented instead of the traditional retention collar to save space but this had to be secured (by paint in this case) to prevent it from moving about. if this C-ring somehow managed to get loose, it will impede the iris mechanism's movement. just like how an ingrown toenail is giving me discomfort now ::)
the bayonet part reminds me of the 85/2's mechanism. while this part is robust, it can be damaged when the stop-down lever suffers enough pressure on impact.
mine had a bent aperture ring. I must note that this lens' aperture ring is easy to get warped due to it's thinness and delicate nature. I had to dremel the bulging part to make it work properly. it is of a brittle but malleable alloy so care has to be exercised so it won't crack