[chochichaeschtli]

You find some serial numbers and dates here:
SMC Pentax-DA* 50-135mm F2.8 ED [IF] SDM Serial Numbers - Pentax Serial Number Database - PentaxForums.com
looks to me like you should avoid getting a 91**** serial and look for something newer than approx. 9296*** - if you can choose . at least you could check after buying.

and information about the redesign here:
Pentax Engineer on SDM Failure and Pentax DC - Photokina 2012 | PentaxForums.com

p.s.
redesigned sdm doesn't mean the lenses are focusing faster

[someguy42]

Thanks!

[normhead]

You could probably make do with a Tamron 90 macro ƒ2.8... not that much money and an excellent lens for IQ as well as one of the fastest focusing lenses but, it is screw drive. Reasonably light, travels well, and razor sharp.

But honestly, if you have the money the DA* 50-135 is what you want to go with what you're got.
Great lens, great IQ, fast enough to use indoors... what's not to like?

[ogl]

If we say about sharp lenses, it's 50-135 and 60-250.

[close-enough]

I vote for the 50-200 wr. It's light-- I carried it all the way across India for 5 months, used it about 5 times and had no regrets, about carrying it-- it's that light.



For example, when I myself was taking a bath and I saw these gentleman doing the same on the sidewalk below my hotel room in Calcutta, I was glad I had the 50-200 with me.

[someguy42]

Size is definitely an issue. Right now, I carry the Sigma 10-20, the Pentax 20-40, and there is just enough space in my messenger bag to tuck the Pentax DA 70mm into the bottom. I could get the 50-135, but I'd have to carry a larger bag, which I'd rather not do. So now, I'm thinking about picking up the 50-200 and replacing the DA 70 with it. Obviously, it would not be as sharp, but I'd gain a lot of focal range and WR as a trade.

[chochichaeschtli]

If size is very important may the 50-200 is ok - but you wont really gain focal range imho. i hardly ever used mine since ive got the 50-135 because using 135mm and cropping looks still better than using the 200mm (may its just my copy). <br />
<br />
so i think its more about weight vs lowlight, bokeh and build quality.

if you keep your 70mm the 50-200 looks like an option. but if you sell it you wont have any fast lens in the upper range.

[zzeitg]

that's true. I got 50-200 together with my K-7 some years ago and from time to time I still use it. But its performance in low light conditions is pretty much limiting.

[chochichaeschtli]

attached you find examples for my statement about cropping.
001/002 shows the case if you don't have a tripod and need shutter speed of 1/180* (and thus open aperture as much as possible and increase iso as well)
003/004 shows the case if you have a tripod and can keep aperture at f/8 and iso100.
i think in both cases the 50-135 shows "virtually" a better zoom range. although you have less pixels (because i cropped more...), the image is still sharper (you can see it better if you compare them at the same size, e. g. fullscreen).

* made a mistake: you would even need >1/200 with the 50-200, i. e. even higher iso. i used a tripod here anyway, so the comparison still shows the tendency

[chochichaeschtli]

but of course the size difference is impressive...

[UncleVanya]

To many great options! The da70 and the 50-200 are miles apart in IQ. What about just adding the 1.4 hd teleconverter. Not cheap, but your 20-40 would be a 28-56, the 70 would be a 98, a bit slower, but useable and compact and reaching you goal of 100mm top end.

[close-enough]

Size is definitely an issue. Right now, I carry the Sigma 10-20, the Pentax 20-40, and there is just enough space in my messenger bag to tuck the Pentax DA 70mm into the bottom. I could get the 50-135, but I'd have to carry a larger bag, which I'd rather not do. So now, I'm thinking about picking up the 50-200 and replacing the DA 70 with it. Obviously, it would not be as sharp, but I'd gain a lot of focal range and WR as a trade.

My photographic style is about getting close with wide to normal lenses, so I'm content with the DA 50-200 as my only long lens. And I'm all about traveling light. With those predilections of mine, if I had the DA 70, I wouldn't get the 50-200, I would just bring the DA 70 on my next trip.

[someguy42]

To many great options! The da70 and the 50-200 are miles apart in IQ. What about just adding the 1.4 hd teleconverter. Not cheap, but your 20-40 would be a 28-56, the 70 would be a 98, a bit slower, but useable and compact and reaching you goal of 100mm top end.

I hadn't considered getting a teleconverter. Do they affect the IQ at all?

[normhead]

I hadn't considered getting a teleconverter. Do they affect the IQ at all?

The Pentax HD DA 1.4 TC seems optically great, for me it doesn't affect quality much at all, if you consider that it's hard to get the same quality out of a 200mm lens you can get out of a 100mm lens. You're going to lose a bit of overall quality, but not in your subject area. I've only used the TC for long lenses.
I'm not even sure what their characteristics would be on short lenses. On my sorter lenses, I want them to be reasonably fast, so losing 1 stop for this TC isn't an option. With longer lenses you take what you can get, or you pay a fortune.

Anyone used the 77 ltd with the TC? Being a 1.8 lens, losing a stop wouldn't be so bad. A 1.4 TC on a 77 would still be about as fast as The DA 70 at 100mm. Taking a 2.4 lens to almost ƒ4 would just be painful, at least for me.

[someguy42]

$500 for that thing? Pfft.