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03-12-2009, 09:28 PM   #16
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QuoteOriginally posted by Jewelltrail Quote
I know what you mean by parallel, and I know what you mean by the sensor plane, but I am confused by the meaning of these phrases in this sentence. Could someone kindly explain further--thanks?

Do you simply mean the if the camera is held level, then the signs you shoot must be level too? If so, why?
What I was trying to say is that it is important when doing a short distance test (i.e. 20x the focal length), that the lens axis be perpendicular to a flat target. (Another way of saying sensor plane parallel to the target plane.) Otherwise, the near/far edges will be soft simply due to being out of focus.

At longer distances, it is not as critical, though it is probably still a good idea to orient yourself straight on to the real estate signs or brick building. (Yes, I know...mine are slanted away from the camera in my test shots...)

Steve

03-12-2009, 10:09 PM   #17
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Thanks to Michael Elenko who points me to a great article by Mike Johnson on "How to stress a lens.." and I am sure I can read it a couple of times to gather ideas from a very admired writer on photography
03-12-2009, 11:06 PM   #18
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QuoteQuote:
Stevebrot: What I was trying to say is that it is important when doing a short distance test (i.e. 20x the focal length), that the lens axis be perpendicular to a flat target. (Another way of saying sensor plane parallel to the target plane.) Otherwise, the near/far edges will be soft simply due to being out of focus.
Thank you Steve. I will keep this is mind if I get to another test someday.
03-12-2009, 11:12 PM   #19
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hinman: Excellent article--thanks. Perhaps it will enable even me to produce a good lens test here someday.

03-13-2009, 12:23 PM   #20
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QuoteOriginally posted by Jewelltrail Quote
hinman: Excellent article--thanks. Perhaps it will enable even me to produce a good lens test here someday.
Thanks for the comment. That is an excellent article by Mike Johnson with lots of detail and samples. And when I look up this topic in testing tele lens, I find another sample of testing short-tele lens as in 85 to 135mm and I now have two references along with many valuable suggestions on this thread as in real estate signs, graveyards, distant landscape for dof, close range for bokeh, etc.

Bokeh can be subjective and it may render different opinions. And I find it cumbersome to test on two separate lens together on bokeh. And I get a short window of time on short distance on the Soligor, mostly in f/4.0 and ISO 200 due to clouds. Straight from jpeq without any post processing.


I don't have trained eyes and experience to look for a pleasing bokeh. Comments and suggestions are welcome

Last edited by hinman; 03-13-2009 at 12:42 PM.
03-17-2009, 12:29 PM   #21
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I took the Soligor 200mm f/2.8 in M42 mount for a morning walk. I have the Komine 200mm f/3.5 with me but I fell short in time and energy to do the comparison. I love taking pictures more so than comparing pictures from different lens.

I find 200mm getting me closer to nature and I feel great carrying the Soligor around in nature walk. The K mount should be better fit as there is certain wobbling on the m42 mount. But the M42 does have the Av mode advantage not requiring the stop-down metering -- critical for reaction time needed in grabbing a shot.

I am not a bird shooter, I have problems in hearing the birds but not finding them easily. I managed to get few sparrows that are quite far away, I end up cropping the shots quite a bit


cropped, f/5.6



cropped, f/5.6



cropped, f/5.6



And a biker snapshots










bokeh shots


f/5.6



f/4.0


Impressions & Notes
  • Some wobbling with the M42 mount due to weight of lens, K mount won't have that problem.
  • But the m42 allows Av without stop-down metering
  • Sharpness is reasonable in close distance as in 10 to 20 feet.
  • I have test shots in farther distance and contrast and resolution is not as good. Pictures are quite soft
  • f/4.0 has a nice balance in bokeh and sharpness
  • I go between f/4.0 and f/5.6 mostly for birds on tree
  • Birds are difficult to nail focus due to their small size, I have quite a number of misses from my test, I should try spot focus
  • 200mm seems way too short to get to birds, a lot of cropping as a result

Comments are very welcome

Hin

Last edited by hinman; 03-22-2009 at 03:45 PM.
03-18-2009, 06:38 PM   #22
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Here are some product shots of my Soligor 200mm f/2.8 in M42 and my Vivitar 200mm f/3.5 from Komine in K mount. The bigger and the bulkier one is the Soligor. I have grown to love the handling of the Soligor though test pictures don't convey good sharpest, bokeh seems decent to me. At the moment, I find I am already biased towards to the Soligor more so than the Komine 200mm f/3.5 that I used to praise about in the past. Bias in the sense that I subconsciously want the komine 200mm not to do as well when I compare it.










Last edited by hinman; 03-18-2009 at 06:50 PM.
03-22-2009, 07:43 AM   #23
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I tried the M42 lens on Pentax F-1.7x TC, the magical AF TC won't AF on the m42 lens but it works better than my 2x kiron doubler.


Soligor 200mm f/2.8 (m42) +
Pentax F-1.7x AF TC
1/250 sec, f/4.0, 340mm, 800 iso, 0 Ev
cropped





Last edited by hinman; 04-03-2009 at 06:03 PM.
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