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Fstop messed up?
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Nov 10, 2015 10:46:01   #
wolfiebear Loc: 10,200 elev. in the Rockies
 
jcboy3 wrote:
Doesn't matter what the aperture label says; you will get the DOF that corresponds to the actual aperture.

Yup -- f22 shuts down like about f11. . . .f16 shuts down like about f8.

That assumes that you are closing the aperture before you shoot.

Sure am.

Simple test is to compare exposure readings at different aperture settings. For example, if you get an exposure of 1/400 at f/3.5, then you should get an exposure of 1/10 at f/22. Whereas, if the aperture is actually f/16 (even though labeled as f/22), then you should be getting an exposure of 1/20.

I can see from the back side of the lens that it is not shutting down all the way . . .and I can see from my photos out the window that it is not shutting down all the way. And I have to change the metering when I switch over to another lens at the same focal length and same fstop setting.

. . . . . Might be a mechanical problem with closing the aperture, or just a design problem. . .
Doesn't matter what the aperture label says; you w... (show quote)


That is what it appears like. Could just be this was a flawed design???? Who knows.
I just used to think this lens was too soft for landscapes, until I ran it through its paces yesterday and figured out there was an aperture problem with it.

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Nov 10, 2015 10:49:10   #
wolfiebear Loc: 10,200 elev. in the Rockies
 
alfeng wrote:
Are you actually able to achieve MORE depth of field with the 135mm Nikon lens than with the 135mm Palinar when the aperture on both lenses is the same when shooting the same object?!?

[b[Yes. TONS more.[/b]

FWIW. I do not think that you can assess the amount of light making it to the theoretical film plane coming through two different lenses which have different maximum apertures based on the appearance of the aperture blades ....

I think that YOU may need to put the two lenses on a common "body" and then meter, accordingly ...

Yup. They are different.

OR, put both lenses on a digital body, set the aperture, and then see if the resultant "shutter speed" is the same-or-similar OR decidely different.

That is the first thing I did yesterday before posting this. Theyu are not the same


Are you actually able to achieve MORE i depth of ... (show quote)

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Nov 10, 2015 11:20:26   #
alfeng Loc: Out where the West commences ...
 
wolfiebear wrote:
Are you actually able to achieve MORE depth of field with the 135mm Nikon lens than with the 135mm Palinar when the aperture on both lenses is the same when shooting the same object?!?

Yes. TONS more.

FWIW. I do not think that you can assess the amount of light making it to the theoretical film plane coming through two different lenses which have different maximum apertures based on the appearance of the aperture blades ....

I think that YOU may need to put the two lenses on a common "body" and then meter, accordingly ...

Yup. They are different.

OR, put both lenses on a digital body, set the aperture, and then see if the resultant "shutter speed" is the same-or-similar OR decidely different.

That is the first thing I did yesterday before posting this. Theyu are not the same


Are you actually able to achieve MORE depth of fie... (show quote)

Fascinating!

Okay, because you are undoubtedly younger than many of us ...

.....And so, using a pre-set lens may not be second nature for you ...

I am going to make what may be an incorrect suggestion that you may not actually be using the pre-set properly ...

Is there ANY chance that you are not remembering to also turn the second aperture ring all the way to the whatever pre-set you have chosen to stop the lens down to?




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Nov 10, 2015 12:15:45   #
wolfiebear Loc: 10,200 elev. in the Rockies
 
I believe there is no chance ;-) but worth asking me. :D :thumbup:
I dial in the aperture . . . and when i go to shut down the pre-set ring, it hits a rock solid place that appears to be about f11 when the aperture ring says f22 (etc. . .)

alfeng wrote:
Fascinating!

Okay, because you are undoubtedly younger than many of us ...


.....And so, using a pre-set lens may not be second nature for you ...

I am going to make what may be an incorrect suggestion that you may not actually be using the pre-set properly ...

Is there ANY chance that you are not remembering to also turn the second aperture ring all the way to the whatever pre-set you have chosen to stop the lens down to?

Fascinating! br br Okay, because you are undoubte... (show quote)

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Nov 10, 2015 17:38:52   #
twowindsbear
 
wolfiebear wrote:
I believe there is no chance ;-) but worth asking me. :D :thumbup:
I dial in the aperture . . . and when i go to shut down the pre-set ring, it hits a rock solid place that appears to be about f11 when the aperture ring says f22 (etc. . .)



THIS sounds like your lens is not functioning properly!

IMHO, of course

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Nov 10, 2015 19:54:35   #
Blurryeyed Loc: NC Mountains.
 
alfeng wrote:
FWIW. I think that YOU (Blurryeyed) are a candidate for a mirrorless digital camera body!

.....A mirrorless camera body will allow you to effortlessly use your Takumar lenses.

Just a reminder ... the Electronic Viewfinders which are (available) on(-or-for) many mirrorless cameras will allow an individual to see what the camera sees in dim light and/or when the lens is stopped down to smaller apertures.





I currently have about 30 of those old lenses, mostly Taks, only one Ziess, a couple of classic Visitors, and some Olympuses that look as if they were never used.

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Nov 11, 2015 00:05:31   #
DJO
 
Do you WANT a Nikon 135mm f2.8 Ais ?

EX+ condition. Low milage, low price. Much, much cheaper than ebay. Depth of field in any amount you want or need, easily obtained. I believe there is a way to send me an e-mail privately.

Just trying to be helpful, no hard sell. If you are happy with what you have, that's great. Best of luck to you.

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Nov 14, 2015 16:01:59   #
zigipha Loc: north nj
 
f8lee wrote:
This bit of misinformation has popped up here from time to time (egads! Is it possible Wikipedia is wrong?)

F stop is the ratio of the lens' focal length TO THE DIAMETER OF THE APERTURE. Not the diameter of the front lens element. Period.

Just look at the 14-24 MM f2.8 Nikkor zoom - do the math with that front element and you can figure it out for yourself. Better still, check out the 8MM f2.8 fisheye they made in the '70's - it's front element is almost a foot across.

In fact, as a further thought experiment - if that erroneous formula were in fact correct, how does a 70-200MM f2.8 zoom maintain that constant aperture when you zoom? The front element does not change in size.

Why that Wikipedia error persists defies logic.
This bit of misinformation has popped up here from... (show quote)


Go look up "entrance pupil" and you will see that wikipeidia is correct. entrance pupil is NOT the diameter of the lens

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Nov 14, 2015 16:55:57   #
Apaflo Loc: Anchorage, Alaska
 
zigipha wrote:
Go look up "entrance pupil" and you will see that wikipeidia is correct. entrance pupil is NOT the diameter of the lens

:thumbup: :thumbup: :thumbup:

And one fairly good source of simplified information about the entrance pupil can be found at:

https://en.wikipedia.org/wiki/Entrance_pupil

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