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09-10-2018, 03:04 PM   #46
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QuoteOriginally posted by normhead Quote

They are in order, 50, 70, 90 100 (and my luggage combination is 1-2-3-4) but you can check by clicking on the image, then scrolling down to see the flickr exif.

Read more at: Macro-bokeh-test - Page 3 - PentaxForums.com
Of course 3 and 4 are the best.
4 blurs the image the most because of the longer focal, but I personally see No.3 as a little smoother.

09-10-2018, 03:38 PM   #47
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QuoteOriginally posted by cyberjunkie Quote
Of course 3 and 4 are the best.
4 blurs the image the most because of the longer focal, but I personally see No.3 as a little smoother.
I honestly would use any of these interchangeably . I like portraits done with the 70, I like the Tamron, but it's kept and used by my wife, I like the 100 because it''s WR, there are times when I use the 50 just for the increased depth of field, when background out of focus areas aren't the critical factor. I like them all for what they are best at.

Last edited by normhead; 09-10-2018 at 05:51 PM.
09-11-2018, 01:08 AM   #48
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QuoteOriginally posted by normhead Quote
I honestly would use any of these interchangeably
I fully agree.
The more you know your lenses, the more you get the subtleties and understand which is best for what.
Of course when OOF rendering is important, longer focals allow to blur the background much more than shorter ones.
I didn't check the link, so I didn't know which optics you used. I was unsure about the 90mm, could have been the new Tamron, the old one, or one of the various versions of the Komine manual focus.
I never tried most of them, but I know that the new Tamron is a hell of a lens.
I have two version of the old one (f/2.5), MF and AF. Very good lenses, and quite cheap. The main problem is the dreaded light spot due to inter-reflection between the back (perfectly flat) glass and the sensor cover. Fortunately I never experienced it with the K-1
I'm not surprised to see you own the 70mm. It's the best of Sigma's macro family, IMHO. Sharpness wise, I'm sure it plays in the same league of the new D FA 50mm (and some leitaxed"blue blood" glasses). Though we can't expect that its magic would work past physical limits (that is: optic laws), so when bokeh comes into play longer focals will blur the background a little more, and give a stronger separation of the planes. Which confirms what you wrote: they are not interchangeable
We know that the difference becomes more evident the closer we focus. Your comparison is interesting just because of that: macro lenses, with their short MFD, allow to highlight the differences due to the particular "character", and specific focal length, of each lens.

I understand your love for the Pentax-D FA 100mm. I acquired the old FA version quite recently. It is an amazing optic! Such sharp, contrasty, crispy pictures! It has a few cons, and one plus, vs the D FA, bu nothing that could really affect the final picture, I guess.
Which means I believe to have a fair idea of how your D FA performs (and why you keep it for yourself ).
Very recently I found a Pentax-A Macro 4/100mm, which has been for a while in my wish list. From the pictures it looked quite battered, and I even spotted a kind of cobweb inside! Fortunately it cleaned up nicely, even the filth on the flocking paper deep inside, and the damage was limited to the filter.
I used it extensively since then. Despite the recessed from element it suffers from flare (low contrast) in extreme lighting conditions, and is a little inferior to the FA sharpness-wise, however most of the times it gives crisp, very sharp pictures, and I'm starting to believe that bokeh is actually better.
I should take the time to compare it with the FA in the same conditions, and see if it's true.
Recently I'm shooting more and more with bokeh in mind, framing the picture in a way that leaves part of the image completely out of focus, and using mid apertures only when required.
Doing that I am completely rewriting the hierarchies of my favorite optics, and found that best sharpness and best bokeh often don't go together.
My gut feeling, yet not proved by any proper test, is that in general the less the lens groups, the best the bokeh. In fact the f/4 100mm has only 3 glass to air surfaces (Heliar design).
I'm curious to find if others had the same impression

Last edited by cyberjunkie; 09-11-2018 at 01:15 AM.
09-11-2018, 02:37 AM - 1 Like   #49
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QuoteOriginally posted by troika Quote
So, to wrap this thread up neatly, the shop with the Sigma 70 still has it. It's a great lens and can be yours for $250 if anyone is interested, I can point you to it and if it helps, I've handled it and looked at it and shot with it and it's in mintish shape and is a great lens.

But, they happened to get in a used Pentax 100/2.8 WR and I bought it for just a bit more. I liked the form factor better, I liked the working distance a bit better. I liked the quick shift and the WR. I also think that if I were to wind up with a K1 that it would be a better focal length.

Lucky that I was able to handle and compare them back to back. They're both fine lenses and it's arguable whether I actually needed that good of a macro lens or not. I always believe that I'm going to use my macro lenses as telephotos too and I think I might in this case, which helps me justify ownership.

Thanks for talking me through it.

just a note on the Sigma 70 - I bought a copy recently and am using it in this month's Single In Challenge

hugely versatile and possibly as sharp as my D FA 50/2.8 Macro

I bought it based on reviews/photos/chatter I've read about the lens online, plus when this copy showed up for sale here on the Marketplace, it was the only the second copy I had ever seen for sale (here, eBay, anywhere else) - so I bought it for a reasonable price

no regrets whatsoever...

09-12-2018, 02:04 AM - 1 Like   #50
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QuoteOriginally posted by pepperberry farm Quote

I bought it based on reviews/photos/chatter I've read about the lens online, plus when this copy showed up for sale here on the Marketplace, it was the only the second copy I had ever seen for sale (here, eBay, anywhere else) - so I bought it for a reasonable price

no regrets whatsoever...
Bought mine second-hand too.
I found that in the end it pays to be patient and wait a little.
Buying from a reputable source, or paying with PayPal on Ebay, leaves little room for potential risks.
Even brand new lenses have to be shipped, or come out "problematic" from the factory.
On many, many purchases I never returned a lens.
A couple of times I asked for a discount because the lens had some undisclosed problems. Most of the time I buy vintage lenses as is, paying somewhat less than the average price. Returning the item would make it a loss.
I just made two huge mistakes: didn't properly check two expensive AF lenses just after the purchase. Later on, when returning was not possible anymore, I found important hidden flaws, that cost me some good money. Both were Sigma's, and now they are among my sharpest and most used AF objectives, but to get there I paid a price I shouldn't have paid.
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