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07-24-2012, 05:42 PM   #1
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Lens Comparison: Tamron 18-250 / Pentax DFA100 WR / Tamron Adaptall 70-210 f3.5

So LBA has sunken it's teeth into me these past few months. I've been brain storming on new lenses, gone so far as to make a spreadsheet of different lens combinations/kits to see if I could come up with a favorite lens combo for myself. I'm sure some of you can relate to this insanity...err I mean hobby! Certainly I realize I should be taking photos with the lenses I have (all of which I love and spent a long time deciding to purchase). However, here I am, posting a comparison test, after picking up the Tamron Adaptall-2 SP 70-210mm f3.5. I picked it up because it was well reviewed, has great build quality, is only half a stop slower than the 'pro' f2.8 zooms, and also has a 62mm filter thread, which is currently the maximum in my lens kit.

Anyway, this post is more just to share my results...for anyone else who has or is considering these lenses. (not to mention, what's the point of doing all the work and not sharing it?)

Test was done on tripod, 2 sec delay, in RAW+ mode. These crops were all done with the out of camera jpegs and losslessly cropped using FastStone Image Viewer (lovely free program btw).

I initially only did the 'brick' wall test...but noticed the Adaptall 70-210mm seems to have much worse IQ at close focus distances. The brick tests were done about 1.25m distance so fairly close to the Adaptalls' close focus of 85cm.

I then did a second test, same setup, but at a bit of a longer range. Probably about 15 meters or so.

If the photos are not showing up for some reason, the entire gallery can be seen here: Adaptall Tamron 70-210 f3.5 Tests - Ryan Senn Fotography | SmugMug

Closer brick test results:




07-24-2012, 05:42 PM   #2
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Here are the results for the second batch of tests at a longer focus distance:




Last edited by Arrvon; 07-24-2012 at 05:56 PM.
07-24-2012, 06:41 PM   #3
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That's just cruel putting the 18-250 @100mm next to the 100 Macro WR, but the Adaptall zoom acquits itself quite nicely here.
07-24-2012, 06:51 PM   #4
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Nice of you to invest the time to do the tests, but the DFA 100 is in a league of its own.

07-24-2012, 10:30 PM   #5

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QuoteOriginally posted by Ash Quote
Nice of you to invest the time to do the tests, but the DFA 100 is in a league of its own.

This is a really good example, however, of why it pays to stop a good lens down just a little. On the brick wall test in particular, you can see that simply stopping the DFA100WR down to f/3.5 makes a significant difference, getting it much closer to its optimum performance.

It's not surprising that the Tamron 70-210 did fairly well - I thought it would.

It's a rather dramatic reminder of the Tamron 18-250's huge zoom range - the fact that the tests had to start at 70mm and end at 210mm, with the 18-250 never being the limiting factor! In fact, you couldn't even test it's entire ~'normal' zoom range of 18-70mm. Notably, it performed pretty well at the long end, at least in the center.
07-24-2012, 10:44 PM   #6
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Couldn't agree more. When I first opened the DFA100 WR pics I was very impressed at how sharp it was, straight from f2.8.

The Tamron 18-250, which I have been more than happy with, suprised me with how well it did on both tests in the center. The borders certainly left a lot to be desired wide open, but that's a well known fact for that lens. I was still happy to see how decent my copy was in the center even at 200-250mm wide open. (ps. it's clearly more of a 135mm lens when focusing close, again another well known fact for the lens)

The Adaptall 70-210 has impressed me overall for an older lens. My copy has been well used, but the optics still look great. It appears that they sacraficed quite a bit of close up IQ at the 200mm range to get to the pretty impressive magnification of 1:2.6. A bit of give and take I would imagine when they designed the lens. Perhaps there is a bit of a centering defect in my copy as it appears that the corners are actually better than the centre at f3.5 when focusing up close.

Another aspect of the lens is some CA at f3.5. Escpecially wide open at f3.5. If you view the above test shots at full resolution, you can see some of it. Nothing too bad though to worry about. Even the DFA100 WR has it when wide open at f2.8.

Overall, i'm very happy with it. Gives me great results wide open...even at 210mm as long as i'm not super close (which isn't something that happens frequently when you reach for a 70-210mm lens in the first place). The bokeh seems quite good for a zoom. Yes it's heavy, but the build quality is great (love all metal lenses!), and it's not a super thick lens as evidenced by the fact it only takes a 62mm filter. I love the hood design as it extends when at the longer focal legths to provide extra shade.

*of note, my copy did not come with the these tests were all done without the hood. Should not really matter given that I was in a shady area while taking the photos*

Next up for a test...the Raynox DCR150 on the Adaptall 70-210!

Here are some non test photos with the 70-210mm wide open at f3.5:

70mm f3.5

f3.5 at 210mm (some post processing to bring the contrast up a bit since this was shot at a close distance)

f3.5 at around 100mm close focus again

f3.5 at close to 210mm if I remember correctly:

f3.5 at around 180mm and I cropped it in a bit (note the CA/purple fringing around the red feeder)


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