Fun with numbers III

Yes even with Roman numerals!

I feel like Portland's NBA franchise right now as I wheel and deal in search of the Right Fit.  They are doing this right now to fill behind the dearly-departed LaMarcus Aldridge .. so why not join them?

As noted previously, I allowed a DA* zoom to depart, traded for two Limited primes.  The DA15 is ideal for me (mind control, already?) and the DA40 is a great little lens.  It's clearly better than my humble A50mm f/2 - but are other needs more glaring, like maybe the big gap from 50 to 135mm?  While the DA70 pairs nicely with the 40 it's too near the 50mm for my tastes.  Perhaps find an excellent 85-100mm prime, keep the 50 and allow the 40 to go in another trade?  Like a base-salary bench warmer the 50 and 135mm lenses have no decent market value, unlike the DA 40.

Hmmm: right on cue: someone is selling their Tamron 90 macro in order to buy Limited primes.  That sounds like a fine trade opportunity that would fill my largest gap and bring 1:1 macro back into the bag, so I'd be picking up a two-position lens with great versatility.  *Update* - the trade negotiations did not pan out so instead I picked up an 'experienced' former star: a KEH "Ugly"-grade smc-M 100/2.8.  No macro but talented and small, which I always like!


The M100 and I have a history, in fact I traded another copy away last season.  This and the M85 f/2 compete for the mid-tele slot much like the DA55-300 and Sigma 100-300 have dueled in the past for the telephoto zoom position.  I'm convinced now that the 55-300 is superior despite its slower focusing, and that the 85 and 100 are sufficiently similar not to worry (or spend!) too much for 15mm and one-stop difference.  For now this is a fine fit for me, so my work here is done.

And so here, yet again, is my kit!
Pentax primes: DA15/4 - K24/2.8 - DA40/2.8 - M100/2.8 -  A50/2 and M135/3.5 in reserve
Pentax Zooms: DAs 18-55WR, 55-300L --  for sale: DAs 10-17, 17-70
off-brand zooms: Vivitar 35-105 f/3.2-4 one-touch, JCPenney 80-200 f/3.5



OK that's enough fake 'roundball' talk.  It isn't my favorite sport, not even top-3.. but for pro sports it's all Portland has. 

the 90 arrives

We were planning a trip that would be ideal for the Q - more precisely the Q and an 06 telephoto lens.  I bought one at a good price and liked it a lot, but then the trip was called off.  While looking for ways to economize on the larger kit I encountered a trade offer of a Tamron 90 f/2.5 for an 06 zoom.  The deal was made, and now the 90mm macro has arrived!

Since this particular version of the Tamron 90 macro (the model 52E) was unknown to me, I read up on it before making the trade offer. Until now I thought that all f/2.5 models were manual focus, so this must be their first AF model.  I also thought all Tamron 90s were 1:1 macros but this one is 1:2.  So much for my general knowledge of early Tamron macros! :^)  It also lacks the bizarre AF/MF clutch that both Sigma and Tamron think are so clever, which may be true with non-Pentax systems.  That alone makes this appeal to me, as I really dislike the two-step focus change!

So this lens has AF, aperture ring and a limiter switch, and takes 52mm filters.  With the limiter set the lens snaps into focus down to about 1:4 which isn't a bad place to change over.  And it really does snap; focus speed is very fast even with no limit set - but it definitely helps to stop the spinning if it isn't needed.  The image quality is extremely good even wide open so it can be used as a general low-light lens and not merely for good closeups.  And if I feel really bold it can be a 180mm f/5 supermacro with the Vivitar macro/TC attached, though I haven't tried this to say how the results might look.

This serendipitous find allows the 85mm f/2 to find a new home, which will pay off a few items on the lens account.  Like the SMC 17mm before it, I find myself forsaking all-manual lenses for AF/auto-aperture and saving some money in the process.  This along with the F17-28 and DA20-40 are very good lenses so whatever happens I'll be just fine.

one last stab at macro + my first Tak

I have mentioned before that I tried several dedicated macro lenses in the recent past.  A Sigma 50/2.8, Tamron 90/2.8, Promaster 100/3.5, Sigma 105/2.8 and a manual SMC-M 100mm took turns, but nothing quite convinced me they would get enough use.  The most convincing was the Sigma, which was a nice 50mm lens with bonus 1:1 coverage.  In the end they all left, and now I have several close-up filter-type diopters and a Vivitar 2x combo teleconverter and extension tube.  These too have not caught on, and I have pretty nearly despaired of taking 'real' closeup shots.

On a parallel track I've been seeking a few good manual-focus primes.  The SMC 17/4 Fish-Eye and SMC-A 24/2.8 are a very good start.  I have a decent SMC-M 50/2 but had hoped for something more 'versatile' whatever that might mean.  I have the DA40xs for autofocus, so a 50mm lens is not vital - but having a set of well-spaced MF primes might catch on.

from bdimitrov.de site

Looking back at me this evening was an SMC-A 50mm f/2.8 1:2 macro at a decent price.  Hmm that would be OK, and would instantly be my best close-focus lens... but I won't bother if it's not any good.  Yikes, this thing scores 9.6+ out of 10 at pentaxforums - that qualifies as really good!  Many owners say it's their sharpest lens, so I'm convinced.

So farewell to the M50, and here's to my one last attempt to use a macro lens.  I've read often that manual focus is as good as AF for really close work, and I did not give the SMC-M 100mm enough time to get used to it, as I was still an AF addict at the time.  Maybe this one will be the answer - or equally likely, after this time I will desist from asking the wrong question!

Hopefully one more MF prime will round it out, though if I find an 85mm I may be forced to add another for the long end.

- - - - - - - - - - - - - - - - - - - - - 
4/11 update - and for now that 'one more prime' is a 105mm f/2.8 Takumar M42 lens.  Serious retro pickup, and a well regarded lens probably from the 1960s.  This copy has lived a full 50 years and it shows, but mere age does not stop a Tak!  Well, so they say; I shall know soon.

This means I have a a Tak, one K-series and two A-series Pentax.  Maybe I should keep the M50/2 around so I have one of each?  Or maybe later I shall find a tweener M - who knows?  Never I, that's certain...

Comparing macros: conclusion?

Wait a minute - plenty of testing remains to be done, and some retesting as well!  

Well..

The whole time I was doing these tests the Tamron was sitting on a few forum sites seeking a buyer.  If it did not sell I would finish all sorts of additional tests, and if it did my budget would be in much better shape.  It sold today, so the testing has reached an unimpressive conclusion.

This is quite unfair to both lenses, but perhaps mostly to the SP 90mm.  Now that I have pinpointed the true center-AF point on my K-5 I should check if that was the reason for the more frequent focus hunting that I experienced with that lens.  That was really the closest thing to a complaint that I had, and it probably accounts for many of the Sigma's missed-focus events as well.

So it's really not possible to say either lens is a winner here - I am the overall winner, for several reasons:

• I had two nice lenses to choose from, so no losing for that
• I now have a 50mm lens that I find satisfactory
• I improved the bank balance going from the 90mm to the 50mm
• I have more space in my bag with the smaller, lighter Sigma - and
• I still have a 1:1 macro lens that gives me excellent results!

So farewell to an excellent lens, and greetings to another!

comparing macros: part two½

Part three intended to swap back to the Sigma right after the Tamron, so I could verify what I thought was different about the two lenses.  Alas, my health failed me so I only took a few images with the 50mm.  So much for plans and some degree of rigor.. but the points that I have hit so far were not refuted.  Focus hunted less with the Sigma and missed a time or two.  A squirrel photo-op with the 50mm came along just like with the 90, but I was at f/3.2 and the focus missed.  To be fair to the Sigma, I believe I have learned that the center focus point on my K-5 is almost precisely at the lower-right corner of the square that displays in the viewfinder.  The Sigma's hit rate shows more success with that in mind (I found this out after the squirrel scene, sadly).  I need to verify this with the Tamron and other lenses, since that is something that should not drift from lens to lens!

After further review - yes the Tamron also prefers the lower-right area of the center-focus square.  And a new item pops up that I had never tested when using the aperture ring on an A-enabled lens.  I had presumed that if I were in Av mode and using the aperture ring in non-A mode, the camera would still know what aperture was set.  It does not - on playback all shots show the max aperture of f/2.8.  Not a big deal, just leave A-enabled lenses on the A setting - but a good thing to know!  I probably knew this back in 1995 with my Program Plus.. but my favorite lens back then was an SMC-M 24-50 so maybe not.

macros compared: part two

A day with the Sigma
Carrying the 50mm macro was nice, a good match to the k-5.  Focus locked in pretty quickly. Let me rephase: the lens was quick to lock down on a point of focus, but a few times the subject I intended was not in focus. I kept the camera in center AF mode.. so this is odd. When it's off it is always back focused, and refocusing did not change the lens' opinion about the point of focus (AF confirms with no lens movement). At other times it locked perfectly though, so microadjusting the lens to a new focus would not solve this. It was easy to see when it happened in the viewfinder so I could shift back an inch or less and get a sharp image - so for me tne workaround was not a major pain. It should not be necessary though!

Exposure and color were nice, and overall I liked working/playing with the Sigma. I did not put on the hood so shading on extreme closeups was less of an issue.. plus it allowed me to use the lens cap (yes, still annoyed by that).

A day with the Tamron
A similar walk with the 90mm came the next day. Right off the bat (a bit before 7am.. both lenses were used at sunrise and noonish) I would say the Tamron hunts more but nails focus more consistently.  If this persists it will make a more interesting choice between these two copies.  Which would I prefer: to rock back for the occasional closeup shot at 50mm, or hum along with the occasional AF whine at 90?  More study needed!

I find the Tamron a bit bulky, but I know that I'm more sensitive than most about size & weight. In fact the Rikenon 70-150 weighs 40g more but is quite skinny, which suggests that bulk is as big a factor to me as weight.   This is an interesting discovery (to me, probably less so to you!).

My lunchtime stroll showed more of the same: great images and a few focus hunts along the way. I did not use the focus limiter with either lens so time to focus was as bad it it gets. Still, it is broad daylight though overcast, so it's too bad an f/2.8 lens is working so hard. A patient squirrel posed for a few shots; the extra reach of the Tamron helped here but I still have a lot of cropping space.

macros compared: part one!

Tamron 90 shot with Sigma 50, and vice versa


So both lenses are now in hand and been given a few simple tests. 
What have I learned in 40 minutes of play?


Well, nothing magical or decisive (not a surprise to me).  Both lenses show very nice color and contrast, decent blur to either side of focus, and similar enough focus speed and noise for me not to comment after changing lenses.  Weight is almost exactly 100g different on our kitchen scale, 300g and maybe 405g with front caps on.

Having used the Tamron for a few months it has the upper hand here, as surprises with that lens were revealed in my distant past. The Sigma surprised me with its screw-on hood: with the hood screwed on, the lens cap cannot attach!  Some would find that a thing worth doing, but Sigma chose not to make it so. Bummer. I suppose the hood protects the lens nearly as much as a cap, but still..

I was using auto WB for these tests so color variation may appear with more detailed testing - but I liked the colors captured by both of them. We had two Easter baskets on the table so it was easy to capture color!  We will wait a while for specifics on bokeh as well, but both easily fall into my "more than good enough" rating.


A few test shots outside with the Sigma were good, but not all.  I shot a twilight-silhouette tree at f/4 to check for fringing; it was evident (green) on a strongly front-focused image, but when the tree was in focus only a smidge of red-cyan was evident.  My torture-test image of power lines showed no big issues.  On a few plant shots I seemed to see some evidence of back focusing, so that will need to be explored and adjusted (thank you K-5!) before honest answers can be had.  Later indoor shots did not show the back focusing, so I will need to pick my adjustments carefully.  A tripod certainly will be helpful too!