[shhh]

Looking to buy an affordable long reach telephoto, and wondering which is sharpest in the 150-270 range out of the following.

Tamron 70-300
Sigma 70-300 apo
Pentax 55-300 dal

Max budget is circa £100.

After it really for longer reach than my current 50-200 for shooting pics of my dogs running. Finding the 50-200 poor in terms if IQ.

Thanks

[rrstuff]

55-300 DAL, if you can get it for 100 pounds. Tamron and sigma should be quite similar. Another option would be a manual focus 300mm.

Also, there is quite a bit you can do with post-processing and shooting at F11.

[esrandall]

55-300 out of those three. I've owned both the Sigma and Tamron, and neither made me very happy. They are both considerably cheaper on the used market than the 55-300, but that's their only advantage IMO.

[jimr-pdx]

I've tried to love others (Tam 70-300, Sigma 100-300 f/4.5-6.7) but above 200mm the Pentax really does shame them. The only one I've heard is close is the Sigma APO model, but the DAL is often quite close to that price. The Pentax' extended range to 55mm is really handy once you start using it.

I'll receive a silver FA-J 75-300 next week, it does not review as well but is easier on the budget ($79 online). Hopefully it will at least outdo the 100-300.

[Des]

Plenty of threads asking much the same question. The almost universal answer would be the Pentax DA-L 55-300. User reviews reflect this:
SMC Pentax-DA L 55-300mm F4-5.8 ED Reviews - DA L Zoom Lenses - Pentax Lens Reviews & Lens Database
Sigma 70-300mm F4-5.6 APO DG Macro Lens Reviews - Sigma Lenses - Pentax Lens Review Database (said to be the best of the Sigmas)
Tamron 70-300mm F4-5.6 AF Di LD Macro Lens Reviews - Tamron Lenses - Pentax Lens Review Database (notorious for purple fringing)

I haven't used either the Tamron or the Sigma, but the Pentax is outstanding value. It is optically identical to the DA and DA WR models. The DA-L lacks quick shift, but so do the Sigma and Tamron. It has a plastic mount, but that has proven quite durable. The DA-L doesn't come with a lens hood, but you can get a cheap one on ebay.

Should be a big improvement on your 50-200. Here's a sample:

[ramseybuckeye]

I've had a few of the Tamrons and Sigmas, all bought used. Even the best couldn't touch the 55-300. The 55-300 does very good with adequate light. If you can swing it get the DA version because of the quick shift. The quick shift allows you focus close manually then hit the auto focus. I say this because the auto focus is slow and noisy and can scare birds away, this technique really helps.

[GeneV]

Another vote for the 55-300. It goes with me every trip (other than trips made just for photos), and replaced the 50-200 in that role.

[percy]

I've had the Tamron and the Pentax.
The Tamron was cheap and good value for money.
The Pentax was much better.

[crewl1]

IQ wise the Pentax would be the choice except the AF is a bit sluggish possibly for running dogs.

I chose the Tamron A17 version due to its quicker AF when I compared the two.
It has a bit of purple fringe issue in high contrast areas but it cleans up easily in post.

[wildman]

Sigma 70-300 apo
180 bucks new
It gets the job done...

[tibbitts]

I have had experience only with the Pentax 55-300 and the Tamron 70-300. I have a copy of both, and have tested other copies, but use the Tamron. I miss the focus clutch, non-rotating front element, generally snappier contrast, and (especially) the 15mm on the low end of the Pentax, but my copy of the Tamron is more consistent across the frame. The Tamron macro mode at 180mm is handy, although both lenses work fine with an achromat as well. The Pentax has more trouble with AF, but it has that focus clutch, so you can more easily help it by getting it close, and then revert to AF. Obviously the Tamron covers full-frame, although the performance on FF might be fairly awful at the edges/corners. My current copy of the Tamron isn't perfect, in that the mid-range is very slightly soft near the right edge (I'm not sure it was always that way, actually, since it took me over a year to notice it, even after extensive testing), and of course you get purple fringing, particularly at the longer focal lengths, in certain conditions. The Tamron would probably be a horrible lens for photographing a bird against a white sky, for example, which I tried once. Software can come to the rescue to some extent, but not entirely.

When you read objective reviews, none of these consumer zooms has outstanding performance, and they just aren't that much different from each other. But with K-mount, the only other (current) game in town, besides the giant f2.8 zooms (really a different category) is the Pentax 60-250, which I'm reluctant to pay for because of the pitiful warranty and service, the greater size/weight, and my limited need for f4 (or even f5.6.) I find f8 (at the shorter lengths) or f11 (at the longer lengths) provides good-enough-for-me performance with these lenses, although often I use even smaller apertures (sacrificing some sharpness to diffraction) for more depth of field.

My main suggestion for these - and actually most - lenses would be that for general photography, the quality of the copy you have will matter far more than whether you choose Pentax vs. Tamron vs. Sigma. When you get a real clunker (several of my grossly decentered Pentax 55-300s, notably), it's obvious, but most lenses will still have some slight manufacturing variations that can still amount to more than the performance difference between brands/models. I don't think there's really any excuse for that being the case, especially not with $1000+ lenses, but it is what it is. I guess lens manufacturing tolerances haven't fully caught up with sensor technology in that what might have been good-enough in the 6mp era just isn't good-enough today. I'm resigned to having to do some QC myself on these $200-$400 lenses, but when you get to a DA* or something, it seems like somebody at the factory should be doing that for you.

Oh, I forgot to mention the Pentax 50-200mm. If you're looking for a huge improvement with these 300mm lenses, I'm not sure it's going to be there. A modest improvement at some focal lengths, maybe. At 200mm or so, yes, I think the fact that that's more mid-range for the 300mm lenses helps them out. Plus with the Tamron and Pentax 300s, you've got an extra half-stop or so at those ranges, which might matter to you.

[wildman]

I believe lens manufacturing tolerances haven't fully caught up with sensor technology in that what might have been good-enough in the 6mp era just isn't good-enough today.

Could be.
My 18-250 Sigma macro HSM is noticeable better than the older Sigma 70-300 in most every respect in spite of being a despised super-zoom.
The superzoom at 250mm f/8.

[tibbitts]

Could be.
My 18-250 Sigma macro HSM is noticeable better than the older Sigma 70-300 in most every respect in spite of being a despised super-zoom.
The superzoom at 250mm f/8.

Quite possibly, and some reports suggest that the 18-300 has raised the bar further beyond the 18-250, although other reports are less enthusiastic. I tried an 18-250mm and the the build quality and autofocus was very good, and it was very similar optically to my less wide-ranging zooms. I decided to go with an f2.8 17-50, though, and so stuck to the 70-300 on the longer end.

[todd]

my first telezoom was tam70-300, then tam18-250 and have been happy with both bc I am not picky and only shoot them for fun. I have nice primes on the shorter end where I care more. I have shot both the above lenses quite a bit though, so when I came across some results through the FA80-320 that impressed me, I picked up a used copy for cheap and to my eye, the IQ really has something over the tammy's, and doesn't perform any worse otherwise...

[tibbitts]

my first telezoom was tam70-300, then tam18-250 and have been happy with both bc I am not picky and only shoot them for fun. I have nice primes on the shorter end where I care more. I have shot both the above lenses quite a bit though, so when I came across some results through the FA80-320 that impressed me, I picked up a used copy for cheap and to my eye, the IQ really has something over the tammy's, and doesn't perform any worse otherwise...

I have the "bad" Pentax 100-300F (4.5-5.6, not 5.8) and the main reason I like the Tamron better is the 30mm extra range and the fact that it's physically smaller. The 100-300 outperforms my 55-300 on the right side at 300mm, and otherwise it's about the same as the other lenses.

I will say that the 55-300 images are generally better overall, just glancing at them, before PP than the other lenses. Maybe due to coatings or whatever but they're definitely "crispier." But the other lenses catch up after PP. So if somebody is doing jpg not raw, and/or not doing PP, I can see where they'd say the 55-300 is noticeably better.