[GaryH]

Regarding the 60-250mm . You should be able to find one for the $950-$1100 range. It is a very nice piece of equipment and has great IQ.

[starbase218]

lighter weight, lighter size

You're not going to notice the 30 grams difference between these lenses. As for size, the Pentax is a bit smaller, but is does extend while zooming.

I briefly played with the Pentax, and even though it's not a big lens when compared to equivalent fullframe lenses (100-400mm), it still looks and handles like a stovepipe. With normal lenses, you put the lens on the body. With either of these, you put the body on the lens.

[bdery]

You're not going to notice the 30 grams difference between these lenses.

That's true, I had the numbers of the various Sigma iterations in mind.

As for size, the Pentax is a bit smaller, but is does extend while zooming.

the Pentax is short enough to enter my messenger bag while mounted. The Tamron is just too long for that.

[starbase218]

If you don't plan on doing any indoor shooting, the f/4 aperture will probably be fine. If you want to shoot bugs, though, keep in mind that the 60-250 has a maximum magnification of 1:6.7, versus 1:3.1 for the Tamron. The closest focus is actually not that different, but the 60-250 won't actually reach 250mm at that focus distance due to the internal focusing mechanism.

[bdery]

If you don't plan on doing any indoor shooting, the f/4 aperture will probably be fine.

I was able to shoot indoors with that lens even with the K20D. With the K-3, I can even close the aperture to increase DOF.

[V.rider]

I was able to shoot indoors with that lens even with the K20D. With the K-3, I can even close the aperture to increase DOF.

Do you think you could shoot indoor sports (hockey, basketball) at f/4?

Is there any specific dates or times of the year other than black friday that lenses go on sale?

[WVRICK]

Great questions. If there is another major sale time I will wait it out.

[bdery]

Do you think you could shoot indoor sports (hockey, basketball) at f/4?

Sure. It all depends on your camera and your tolerance to eventual noise. With the K20D, I was never comfortable going higher than ISO 800, with the K-3 I rick at ISO 3200 and more. But f4 will let you shoot in low light situations like your typical basketball court. A hockey rink is usually quite bright, no problems there I'd think.

I suggest you read this:

Pentax DA* 60-250mm F4 Review - Introduction - PentaxForums.com

Is there any specific dates or times of the year other than black friday that lenses go on sale?

Black Friday is sadly a good time. Otherwise, look around. I got mine from Prodigital for 1150$ shipped.

[V.rider]

Regarding the 60-250mm . You should be able to find one for the $950-$1100 range. It is a very nice piece of equipment and has great IQ.

Where?

[starbase218]

I was able to shoot indoors with that lens even with the K20D. With the K-3, I can even close the aperture to increase DOF.

True, I shot the 60-250 indoors as well. But imho the Tamron 70-200/2.8 is better suited to that kind of photography than the weather-sealed 60-250/4.

[V.rider]

I have a barely used 60-250mm for sale as well. I'll be adding it to the main post shortly.

PM me the details before you post. I'm definitely interested?

[GaryH]

Where?

In the Marketplace. Just be patient and you will be able to find one. They come up every so often.

[MadMathMind]

You may also wish to consider the legacy Sigma 70-200 f/2.8 HSM II:
Sigma 70-200mm F2.8 EX DG APO Macro HSM II Lens Reviews - Sigma Lenses - Pentax Lens Review Database

It is a bit heavier than the Tamron or the Pentax (by about 200g), though. This is the older version that lacks OS, which is totally redundant if you have it in the camera body. The newest version of the Sigma adds the weight for OS, although it does have a different optical formula. You can find this lens for $700 and less, if you look for a bit.

Basically, the difference with the Tamron is that this Sigma has an HSM motor. It will be quieter and probably faster than the screw-drive of the Tamron, although both of those will be alleviated a bit if you are using the K-3.

[RGlasel]

Do you think you could shoot indoor sports (hockey, basketball) at f/4?

Absolutely, and less than f/4 might not give you enough DOF to get two players in focus, even when they are in close proximity. I've shot sports at ISO 8000, and with some noise reduction done in Lightroom, had good results. The OP wants to shot butterflies and birds, so I understand wanting to replace the DA 18-135, but if you can get close to the court or rink, it has enough reach to get across and the DC AF is fast enough to get good focus as the distance between you and the action changes quickly. But that's another topic.

[Venturi]

If prices were equal, or the budget allows, I would take the 60-250 without reservation.

I have owned the 70-200 for 4 years now and it is a great producer. But - it's heavy and because of its conical barrel it's uncomfortable to hand-hold. AF is rather loud. I did not care for it as a portrait lens on APC-C; for a portrait zoom 70mm is too long at the short end. I also found the build quality so-so. Tamron has a great warranty program (6yrs), but the fact that I have had to use it on every Tamron lens I've owned is disconcerting. Mine has been sitting in its bag on the shelf more than not for the past 2 years. I keep it for the once in a blue moon times when I need the extra reach past 135mm and don't want to carry 2 lenses.