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Preview: Tamron SP 15-30mm f/2.8 Di VC USD
#21
As a follow-up to the earlier discussion about flare tests:

 

This is a selection of shots I made while field-testing the Tamron.

 

First scene, shooting into the sun, partly covered by the building in the shot.

 

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As you can see, there are some flare blobs both on the building (near the sun) as well as in the foreground.

 

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Plus a few tiny spots near the image center.

 

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Now let's turn the setup by 90 degrees:

 

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Gives us very similar flare results, a reddish shape on the building plus a huge green blob in the foreground. Both roughly in the center of the image.

 

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Now let's move the light source a little to the left:

 

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More or less same results, but now quite a bit apart, the red spot moving with the light source, the green blob moving in the opposite direction:

 

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Same lens, different location, but roughly similar light setup: shooting directly into the sun, more or less centered.

 

Portrait mode:

 

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Surprise: no huge blobs, just some tiny, but colourful spots in the image center:

 

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Let's switch to landscape mode:

 

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Flares in this one? Nope.

 

(Well, ok, maybe there are, but might have ended up in places where there is no dark structure, so they're just not visible)

 

So, to summarize: you can see with these shots how different flare can be with the same lens (and at the same settings in all of the above shots, which is 15mm f/8), even with a roughly similar lightsource. I can't imagine any way to set up a test scenario that first of all offers the same and reproducible lighting conditions (outdoor??) and in addition gives meaningful results that can be compared between several tested lenses.

 

-- Markus

Editor
opticallimits.com

#22
I'll do now the easy part and suggest and indoor test setting, but as I know from my own little equivalence comparsion (which tells a very much different story than the one from people using tables, DoF calculators and normal calculators), the work load is pretty high.

 

However, a dark room indoors situation with a strong light source (these days LEDs draw a lot of lumen out of a couple of watts) would be my setting. I think of the long walkway in our cellar...

tripod and geared head the basis for some reproducible angles at alway the same focal length. Not the expensive Arca-Swiss crap which is only geared in two orientations (that goes for the cube as well, shame). It needs a Gitzo Athena, second hand you could get one for say 5 grand? Just because it has digital angle scale and you could do the rotation and tilt by the laptop... also it looks very good. Highly professional...

 

And here comes the weak spot of the plan: It is dull beyond brain death and nobody will ever find the same conditions in nature, meaning this tests will consume a lot of lifetime of somebody and has to be called useless. The only thing it could do is find out with a lot of effort, how much flares are shown.

 

Flare is a downside of a lens, true, and I say that as user of THE flare collector 14-24/2.8. But there are also good ways to get that out of a picture. So, if a picture is at first "ruined" by flare* I'm better off by thinking how much other great shots the lens already gave me and bite the lemon, use some time to separate the frequencies and bring it down.

 

* which will only distract yourself and a couple of buddies of forums and photoclubs who still write the word "flair" - forget about them, if they see flare at first, the next thing they do is pixel, first counting then peeping, just a preparation to zip the equivalence calculators out of the pocket.

#23
Quote:Flare is a downside of a lens, true, and I say that as user of THE flare collector 14-24/2.8.
THE flare collector is officially called a different name... the Sigma 14mm f/2.8. I can scarcely imagine a lens that would be more prone to flare than that. Smile

#24
Thanks for the follow-up Markus. I see the problem.

  


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