[Laurentiu Cristofor]

I've been looking at the various offerings of tele zooms that reach somewhere in between 200-300mm. I have the DA 55-200.

I checked the photozone reviews and I noticed pretty much all of the budget offerings suffer from CA at the long end.

Tamron 70-300 - looks like it has the best resolution in 200-300 range, but has heavy CA as well in that range.
Pentax 55-300 - better CA than the Tamron at 200mm, but worse resolution at 300mm - also, slightly slower at these focal lengths
Sigma 70-300 "APO" - weak at 300, plus similar CA as the Tamron

The only nice zoom I've seen that gets close to 300mm is the new DA* 60-250mm, but of course, that's no budget offering.

Why are people usually recommending the Pentax or the Sigma over the Tamron when the performance at 300mm is worse? Are the photozone results skewed by bad samples?

[Marc Sabatella]

There are quite a few threads already comparing these lenses - you might want to look for those. But I'd say most people would say the 55-300 *is* better than the Tamron in pretty much all respects, photozone notwithstanding. The Sigma's only advantage over the Tamron is usually said to be less PF.

[SpecialK]

I assume you mean you have the 50-200.

In my side-by-side test (posted sometime ago) that lens was only very slightly sharper and contrastier than the Sigma APO (at 200mm). The Sigma improved a lot by bumping the contrast at the long end.

The Pentax 55-300 is significantly better than either above lens. No experience with the Tamron, though I have seen nice shots will all three lenses.

My Sigma suffered an aperture blade death, and the 50-200 was involved in a lens purchase. I never used either one after getting the 55-300.

[Laurentiu Cristofor]

There are quite a few threads already comparing these lenses - you might want to look for those. But I'd say most people would say the 55-300 *is* better than the Tamron in pretty much all respects, photozone notwithstanding. The Sigma's only advantage over the Tamron is usually said to be less PF.

Mainly I am wondering about how to reconcile the recommendations made on such threads with the results I see on photozone. Is it a matter of sample variation given that these are all budget lenses and QC is an issue?

I assume you mean you have the 50-200.

Yes. Thanks. I'm always mixing the lower FL up.

[Marc Sabatella]

Tough to say how much is sample variation and how much is differences in how the tests are performed. MTF - which is what photozone uses - is kind of a "simulation" of measuring sharpness more directly using actual images as perceived by actual people, and it's conceivable to me that a lens could occasionally do better or worse in MTF than in practice. Anyhow, I just figure after having read literally *hundreds* of opinions from people comparing these lenses - some version of this thread has been posted virtually every month for the last several years, bpth here and on dpreview - there is just way way too much evidence the 55-300 beats the others to bother questioning it.

[Ecaterin]

I've been looking at the various offerings of tele zooms that reach somewhere in between 200-300mm. I have the DA 55-200.

I'll put in my usual recc. for the Pentax FA 100-300 4.7 - cheaper than any of those above, and a better performer in many ways.

Sharp, great color, very low CA and very good contrast (I may bump contrast in PP with this lens, but never sharpness or color and I've never had to PP any CA from this lens yet). Check out the link above (10 reviews gives you a good sample example and my review has a bunch of demo photos) - this lens is a great 300mm for the money (right around a hundred dollars) and in fact out performs lenses that cost a good deal more

You reach a point where all the lenses in your chosen length & size are similar, so you just have to look at hundreds of photos and start to get a sense of what the character of each of those lenses looks like to you

[Laurentiu Cristofor]

I'll put in my usual recc. for the Pentax FA 100-300 4.7 - cheaper than any of those above, and a better performer in many ways.

I'll look for it - thanks!

[Laurentiu Cristofor]

On photozone, the DA55-300 appears to have as much PF as the Tamron 70-300 @300mm. I am wondering if that is another aspect that only shows in the photozone review.

BTW, I got the FA100-300 f/4.7-5.8 that Ecaterin recommended, thanks to a tip from her. I am impressed how sharp that lens is around 100-150mm. It also doesn't have much PF, but it does have LoCA. I haven't been lucky to catch any birds with it at the long end, so I'll need more time with it. I haven't used it much at 200 either. I like that it has more focus throw around 5m-infinity, so it's easier to adjust focus manually.

[hcc]

I've been looking at the various offerings of tele zooms that reach somewhere in between 200-300mm. I have the DA 55-200.

In the range, you include the DA18-250mm, it it not ?

Like many zooms, the 18-250mm suffers from lens distortions. The software PTLens is very useful (at a very moderate price) for lens distortion correction, including fpor all the zooms that you listed.

[Jodokast96]

The Sigma APO is the best performer with regards to CA and PF. The Pentax is slightly behind, and the Tamron is way in the back. It's not called the Purple Monster for nothing.

Sharpness is probably in the reverse order, though the Pentax and Tamron probably flip-flop depending on specific lens samples. The Sigma is behind by a little bit.

I'd place them Pentax, Sigma, Tamron.

[audiobomber]

The Sigma APO is the best performer with regards to CA and PF. The Pentax is slightly behind, and the Tamron is way in the back. It's not called the Purple Monster for nothing.

Sharpness is probably in the reverse order, though the Pentax and Tamron probably flip-flop depending on specific lens samples. The Sigma is behind by a little bit.

I'd place them Pentax, Sigma, Tamron.

As an owner of the Pentax and Tamron, and as someone who's read too many threads comparing them, I agree with the above. One point I would add is that the DA 55-300 has the best colour and contrast, which makes it look sharper, even though this characteristic would not show in the Photozone test. Contrast is a factor in PopPhoto's Subjective Quality Factor (SQF) measure, and as a result the Pentax smokes the others in the PopPhoto tests.

[Laurentiu Cristofor]

I ended up getting the Tamron as well. It's a pretty well built lens for its price and I like its macro feature. I played with it a bit today and I only got purple fringing in one scenario. So, it doesn't look like that is necessarily such a big problem.

In the range, you include the DA18-250mm, it it not ?

It slipped my mind because it's been discontinued. Any idea why that happened - it must have been in production just a couple of years. Is this lens competitive given its long zoom range?

BTW, playing with these long zooms, I discovered that the front rotating element is actually an advantage. I can stabilize better the lens by holding its front with my left hand and now I can also adjust focus that way too.

[Adam]

I ended up getting the Tamron as well. It's a pretty well built lens for its price and I like its macro feature. I played with it a bit today and I only got purple fringing in one scenario. So, it doesn't look like that is necessarily such a big problem.



It slipped my mind because it's been discontinued. Any idea why that happened - it must have been in production just a couple of years. Is this lens competitive given its long zoom range?

BTW, playing with these long zooms, I discovered that the front rotating element is actually an advantage. I can stabilize better the lens by holding its front with my left hand and now I can also adjust focus that way too.

AFAIK that lens was manufactured by Tamron, so I'm assuming they've either discontinued it, or Pentax decided to stick to their own products (maybe a Hoya decision?).

BTW, for others facing this dilemma, I can recommend a cheap but well-performing alternative: the FA 80-320- Pentax Lens Review Database - SMC Pentax-FA 80-320mm F4.5-5.6 Lens Reviews That is, assuming one can be acquired used.

[hcc]

It (DA18-250mm) slipped my mind because it's been discontinued. Any idea why that happened - it must have been in production just a couple of years. Is this lens competitive given its long zoom range?

Yes. The DA18-250mm is regarded as one of the best all-around lenses among all brands incl. Canikons and co. It has been discontinued but you can find some good 2nd hand on the market. It is a rebadged Tamron 18-250mm, and both the DA18-250mm and Tamron 18-250mm are excellent. They are not prime lenses, and suffer distortion that can be easily fixed with PP (eg. PTLens software); but otherwise, excellent lenses that are used by professionals as well as newbies...

[Laurentiu Cristofor]

I just got out today with the FA100-300 and I am pleased with the performance at 300mm. I don't think I can expect much more from a budget lens. Purple fringing is almost inexistent or minimal in the worst case. LoCA can be annoying in certain scenarios, but it's not a big problem.

I posted a couple of shots in the inexpensive telephoto thread. And here's a third one.

Finally, here are a couple of shots - a full frame and a 100% crop:

Full-frame, no processing:



100% crop, with some small PP: curve and unsharp mask:



I'll post some impressions about the Tamron as well, after I'll spend some time with it.

UPDATE: The images embedded above were actually shot at 135mm, not at 300mm; the other shots linked to are 300mm.