[Mattias]

Hi everybody,
this is my first post. I own a Pentax K20D and have a standard zoom lens, 18-55mm. After have taken about two thousands pics I would like a zoom lens with greater range. I mostly walk around in nature and would like a zoom lens suitable for that. I'm thinking of either Tamron 18-250mm 62mm dia or the new Sigma 18-250mm 72mm dia. Which do you think would be a better choice, although there are no tests of the Sigma yet, would Tamron be a better choice anyway? The Tamron lens got good scores at photozone.de. What impact has the Sigmas greater lens diameter? As you can guess, versatility is more important than pro grade, however, I don't want a "bad" lens.

Thanks for any input!

/Mattias

[deadwolfbones]

I'd personally recommend getting two lenses. The Sigma 17-70mm and the Pentax 55-300mm, for example. The convenience of having one lens for the entire zoom range is nice, but there are inevitable image quality compromises.

[ve2vfd]

From the reviews in the lens database, you cannot really go wrong with the Tamron 18-250mm... as long as you understand that you are trading some quality for versatility. It's definetly not a bad lens!

Personally I use the Tamron 17-50 f2.8 and the Pentax DA 55-300 to cover that range. Not as versatile as I do have to carry 2 lenses and change when needed, but image quality is a bit higher.

It all depends on what you prefer of course.

Pat

[PentaxPoke]

Hi everybody,
this is my first post. I own a Pentax K20D and have a standard zoom lens, 18-55mm. After have taken about two thousands pics I would like a zoom lens with greater range. I mostly walk around in nature and would like a zoom lens suitable for that. I'm thinking of either Tamron 18-250mm 62mm dia or the new Sigma 18-250mm 72mm dia. Which do you think would be a better choice, although there are no tests of the Sigma yet, would Tamron be a better choice anyway? The Tamron lens got good scores at photozone.de. What impact has the Sigmas greater lens diameter? As you can guess, versatility is more important than pro grade, however, I don't want a "bad" lens.

Thanks for any input!

/Mattias

I have the Pentax 18-250 which is essentially the same lens as the Tamron. It is the most versatile lens I have. The only reason I don't use it all the time is because I do alot of indoor sports shooting where I need larger max apertures. For a flexible all-around nature lens, it is a very nice option so you don't have to keep changing lenses. It is the only lens I brought with me to Yellowstone. This is the picture I like to show that I took with the 18-250:



It was nice to be able to quickly switch between wide angle to "get it all in" then to zoom to reach out and see the bubbling cauldrons.

You will not see any IQ compromises with this lens unless you pixel peep at 100% crops.

[Mattias]

So what are you guys think of the new Sigma 18-250? How do you think it will perform against the Tamron with larger lens diameter and HSM? In the future I would like to own a Sigma 17-70 and a high quality telezoom but for now I would like to hear your opinions about these two. Especially what the difference in lens diameter would do for IQ and low light shooting.

/Mattias

[PentaxPoke]

So what are you guys think of the new Sigma 18-250? How do you think it will perform against the Tamron with larger lens diameter and HSM? In the future I would like to own a Sigma 17-70 and a high quality telezoom but for now I would like to hear your opinions about these two. Especially what the difference in lens diameter would do for IQ and low light shooting.

/Mattias

There is no way to know until it is tested. Larger lens diameter does not necessarily mean an improved IQ. My understanding is that the new Sigma is supposed to be f/3.5-f/6.3 which is exactly the same as the Tamron. Therefore, there can be no improvement in low-light shooting.

[Mattias]

There is no way to know until it is tested. Larger lens diameter does not necessarily mean an improved IQ. My understanding is that the new Sigma is supposed to be f/3.5-f/6.3 which is exactly the same as the Tamron. Therefore, there can be no improvement in low-light shooting.

This perhaps belongs in another section, but generally, if two lenses has the same f-number(s) and same focal length(s) but differ in lens diameter. How will you notice the larger diameter when shooting? Or is it just a design issue, that a larger diameter is required to keep f-number(s) down?

/Mattias

[PentaxPoke]

Lens diameter is directly proportional to lens focal length and inversely proportional to f number. That is why long lenses with large apertures are very big and heavy, and expensive. There are other factors that go into the final lens diameter. I really don't think you ought to wrap yourself around an axle worrying about lens diameter as it relates to IQ. The Tamron and Pentax are available now and are both highly regarded. If you don't need the lens right away, you can wait to see if the Sigma will eventually be made for the Pentax and then wait for some reviews. I can't imagine it would be a noticeable improvement over the others, but who knows.

[emalvick]

I think lens diameter is just a design issue. While it is strongly related to focal length and aperture, for two similar lenses, a difference in diameter is likely due to the glass to get those characteristics. Perhaps one lens uses more elements than the other, etc. In lens construction, there is more than one way to get the same product although that might be where the quality differences become noticeable.

This is why you see all the comparisons on these forums over which lens is better or sharper amongst the major lens manufacturers.

As for your original question, my solution was to go for a 70-300 mm lens (Tamron in my case) so that I had 18-55 and 70-300 covered. I did this at the time I bought my camera, which was before the 55-300 came out and when I couldn't afford much else. I've been happy with the combination. I rarely feel a need to jump back and forth amongst the lenses, and the whole reason for getting a dSLR is so you can change lenses when needed.

[Mattias]

Yes, I agree two lenses to cover the range would be preferrable. But I have setup a budget for a tripod, an external flash and one lens for now. Since I'm new to photography I don't want to blow too much money on this in case my interest for photography declines. That's why I would like a superzoom so I can experience both wide field and tele photo with one lens. Is it a bad investment, should I go for a quality normal zoom e.g. a 17-70mm? Or perhaps drop the flash for a second lens?

Thanks,
Mattias

[jesalonen]

If you mainly walk in the nature, the flash is perhaps not the 1st thing you need. There are of course lots of things to photograph while walking - I suppose you don't catch many birds in flight either with superzoom or budget telezooms, due to the slow max aperture and weather conditions in Finland. I'll vote for Sigma 17-70: it is wide enough for most landscapes and while not a true macro, it has decent close-focusing abilities. For the price it seems to be a real winner, if you get a good copy. I have gone a long trial-and-error route, and it has costed me a lot, so I would advice to get one good lens (and a good tripod) and see what you can do with that and then concider what kind of a lens you'll need next - which depends on what you most like to shoot and in what conditions.

Best wishes,

Jari

[PentaxPoke]

Yes, I agree two lenses to cover the range would be preferrable. But I have setup a budget for a tripod, an external flash and one lens for now. Since I'm new to photography I don't want to blow too much money on this in case my interest for photography declines. That's why I would like a superzoom so I can experience both wide field and tele photo with one lens. Is it a bad investment, should I go for a quality normal zoom e.g. a 17-70mm? Or perhaps drop the flash for a second lens?

Thanks,
Mattias

I really think your plan is a sound one. Tripod, a good flash (like the Pentax 360 or 540), and a good flexible zoom is a great way to start, and be able to handle all sorts of situations.

[Mattias]

Now I have been wondering if I should complement my kit zoom with a Pentax 55-300, the kit zoom takes good photos. How do the Pentax 55-300 compare to the Tamron 18-250mm in terms of IQ and all-round quality?

/Mattias

[Mattias]

If you mainly walk in the nature, the flash is perhaps not the 1st thing you need. There are of course lots of things to photograph while walking - I suppose you don't catch many birds in flight either with superzoom or budget telezooms, due to the slow max aperture and weather conditions in Finland. I'll vote for Sigma 17-70: it is wide enough for most landscapes and while not a true macro, it has decent close-focusing abilities. For the price it seems to be a real winner, if you get a good copy. I have gone a long trial-and-error route, and it has costed me a lot, so I would advice to get one good lens (and a good tripod) and see what you can do with that and then concider what kind of a lens you'll need next - which depends on what you most like to shoot and in what conditions.

Best wishes,

Jari

Hi Jari!

I would really love to have the reach to capture birds, but I suppose you're right, the budget zooms are too slow. But do you think the Pentax 55-300mm would be a viable choice for birds in water or on ground? I have really thought of the Sigma 17-70, it seems to be a nice lens with good reviews but it feels like it wouldn't add much to my current zoom, correct me if I'm wrong.

Kind regards,
Mattias

[Vylen]

Now I have been wondering if I should complement my kit zoom with a Pentax 55-300, the kit zoom takes good photos. How do the Pentax 55-300 compare to the Tamron 18-250mm in terms of IQ and all-round quality?

/Mattias

That's what i've pretty much done.

The 55-300mm is fantastic. Unfortunately I can't really talk about the Tamron since i don't have it.

But here's a few shots i've taken this week - all at the 300mm length of the lens... I absolutely enjoy taking photos like that. The only processing done on these photo's are the odd crop here and there.


Chase the balloon on Flickr - Photo Sharing!


Concentrating Claridge on Flickr - Photo Sharing!


UNSW Main Walkway on Flickr - Photo Sharing!


At the ready on Flickr - Photo Sharing!


Hard days work on Flickr - Photo Sharing!


AMP Tower on Flickr - Photo Sharing!

Fullsize's available on the links below each image - meta data is intact. Cropping done in Lightroom.

Also, all photos taken handheld.