[atlrob]

I am starting out my dslr experience with a K-X and want to purchase a wide angle lens. I have narrowed it down to two Sigma lenses.

The Sigma 10-20mm f4-5.6 and the Sigma 10-20mm 3.5 HSM.


I believe I understand the differences but would like advice as to whether the less expensive lens (f4). is a suitable choice for a newbe like myself or will I regret not spending the extra $200 for the 3.5. I envision using this lens indoors more than out so the HSM focus seems to be a bit of overkill but don't know that for a fact.

Thanks for the input

R. Burns

[hangu]

The f4-5.6 is not constant, at 10mm it will be f5.6, I'd say that's quite a difference from a constant f3.5. If you're shooting indoor mostly with poor lighting, that extra light is going to help a lot.

Then again, it's a wide angle lens, coupled with an excellent noise controlled camera like the K-x. f5.6 is perfectly usable at a slow shutter speed and high ISO. You'll most likely have to decide if the $200 is worth it.

[Marc Sabatella]

Isn't it the other way around - f/4 at 10mm, f/5.6 at 20mm? f/4 at 10mm is a piece of cake and not to be the slightest bit worried about. f/5.6 at 20mm is a bit more of a drag, as it's the 20mm end where you'd need a faster shutter speed. How much of an issue depends on what you see yourself using it for. Most wide angle shots would be done stopped down more anyhow to maximize DOF and give you edge-to-edge sharpness. For static interiors, even f/5.6 is usually enough to handhold reaosnably. For candids and so forth, you're probably better off switching to the kit lens if you have it.

[jct us101]

Isn't it the other way around - f/4 at 10mm, f/5.6 at 20mm? f/4 at 10mm is a piece of cake and not to be the slightest bit worried about. f/5.6 at 20mm is a bit more of a drag, as it's the 20mm end where you'd need a faster shutter speed. How much of an issue depends on what you see yourself using it for. Most wide angle shots would be done stopped down more anyhow to maximize DOF and give you edge-to-edge sharpness. For static interiors, even f/5.6 is usually enough to handhold reaosnably. For candids and so forth, you're probably better off switching to the kit lens if you have it.

Yeah you're right, it's f/4 on the wide end to f/5.6 at the telephoto end of it. It's such a wide angle lens that it takes in so much more light than anything else you've probably used that paying the extra money for the f/3.5 constant version might not really be worth it if you're on a budget or something.

The newer one is said to have a little bit better image quality though, but the original one (I actually had it once) has some great image quality and low distortions on it's own.

[hcc]

I would recommend to read some independent reviews of the two lenses by www.photozone.de and www.slrgear.com. (Both sites are respected by Pentaxians for their independece.)

The Sigma 10-20mm f3.5 HSM was recently tested by slrgear.com: "Sigma has made some dramatic improvements in this constant-aperture version of the 10-20mm lens, and has made them where they count: at the 10mm end of the focal length spectrum, where (arguably) the majority will probably use this lens. The lens is very sharp, though we're seeing slightly more CA than we did in the previous version. [... But ] The original Sigma [10-20mm f4-5.6 EX DC HSM] ultrawide-angle zoom still holds its own, being slightly sharper at the telephoto end of its spectrum than the newer version. CA is also slightly better in the older version, though the newer version improves on corner shading and distortion." (Sigma Lens: Zooms - Sigma 10-20mm f/3.5 EX DC HSM (Tested) - SLRgear.com!).

Photozone.de tested the Sigma 10-20mm f4-5.6 EX HSM with a Pentax mount, and the lens was praised: "The Sigma AF 10-20mm f/4-5.6 EX DC showed an pretty impressive performance with a few bugs. The resolution characteristic is generally very good to excellent. [...] The CA characteristic (color shadows at the image borders) is generally pretty good except in the extreme corners at 10mm. The build quality of the lens is very high and leaves nothing to be desired. " (Sigma AF 10-20mm f/4-5.6 EX DC (Pentax K) - Review / Test Report). The same site (photozon.de) tested also the Sigma 10-20mm f3.5 HSM: "The new Sigma 10-20 mm f/3.5 EX DC HSM leaves us with mixed feelings. The build quality of the lens is certainly excellent, distortion is a little high at the wide end (but excellent for the rest of the zoom range), there's also a fair amount of vignetting and CA, but that's typical for this lens class. Resolution in the center is excellent, borders also are nothing to complain about and corner performance is ok at 15 and 20 mm, but very disappointing at 10 mm. In summary, it makes one wonder who's supposed to buy this lens." (Sigma EX 10-20mm f/3.5 EX DC HSM - Review / Test Report - Sample Images & Verdict)

Both sites more or less suggested that the newer 10-20mm f3.5 was not a major improvement from the older model "unless you really need the speed of this lens, but for those use cases the Tokina 11-16/2.8 is probably the more attractive option" (Sigma EX 10-20mm f/3.5 EX DC HSM - Review / Test Report - Sample Images & Verdict).

These reviews are worth to read because they suggest some lens alternative options.

Hope that the comment will be useful...

[Pentaxor]

the fixed aperture speed is not worth the expenses for such a lens IMO. usually such lens is used or shot at lower apertures like f8 and over due to depth of field relevance in shooting landscapes or anything with a necessary clear and solid background illustration (not shallow). unless of course if such lens displays a strong resolution of the image borders and corners at higher or wide open apertures which I dont believe that either lens possesses. that means you'd be better off with the cheaper 10-20 Sigma and just spend the extra $200 on a few good faster primes for shallow DOF use and lowlight shots. you could buy a manual focus 35/2, 50/1.4, and a 100/2.8 or 135/2.8 for that amount, thus leaving you with 4 lenses with varying focal lengths to cover the necessary and important ranges as opposed to only having 1 lens.

[Ben_Edict]

If you use the lens mainly indoors, the faster f/3.5 modell would be my choice. I have the older version and find it difficult to focus under dim lighting. Otherwise, the newer modell is probably noticeably bigger. As this is a new lens, real user experiences will be scarce as yet.

For almost all purposes the old 10-20 satisfies my needs nicely and for the rare circumstances, where I really would squeeze out the last bit of image quality or need a somewhat faster lens, I use primes.

Ben

[Ben_Edict]

Both sites more or less suggested that the newer 10-20mm f3.5 was not a major improvement from the older model "unless you really need the speed of this lens, but for those use cases the Tokina 11-16/2.8 is probably the more attractive option" (Sigma EX 10-20mm f/3.5 EX DC HSM - Review / Test Report - Sample Images & Verdict).

These reviews are worth to read because they suggest some lens alternative options.

Unfortunately the Tokina is not available in Pentax mount, otherwise it would be an interesting proposition.

Ben

[glanglois]

Unfortunately the Tokina is not available in Pentax mount, otherwise it would be an interesting proposition.

Ben

It would also be in my bag by now!

Seems ideal for interiors of cathedrals, palaces, museums, etc. I'd happily sell my 10-20 4-5.6 and live with the financial difference.

This is the one area in which the whole Pentax-Tokina arrangement is crimping me. I wish they'd play nicely together .....

[aleonx3]

the fixed aperture speed is not worth the expenses for such a lens IMO. usually such lens is used or shot at lower apertures like f8 and over due to depth of field relevance in shooting landscapes or anything with a necessary clear and solid background illustration (not shallow). unless of course if such lens displays a strong resolution of the image borders and corners at higher or wide open apertures which I dont believe that either lens possesses. that means you'd be better off with the cheaper 10-20 Sigma and just spend the extra $200 on a few good faster primes for shallow DOF use and lowlight shots. you could buy a manual focus 35/2, 50/1.4, and a 100/2.8 or 135/2.8 for that amount, thus leaving you with 4 lenses with varying focal lengths to cover the necessary and important ranges as opposed to only having 1 lens.

It all depends on your usage - if you want to use it indoor with flash (including people) - f8 is not going to cut it; but if you use it mainly for indoor (without flash), that should be okay.

[atlrob]

Appreciate all the thoughtful answers/suggestions. This sure is an outstanding forum for learning. After considering all the reply's and visiting the suggested web sites I have decided to go with the Sigma 10-20mm f4-5.6. Am looking forward to using this lens and knowing me I will be back with a question or two. Thanks again.

R. Burns

[Digitalis]

in regards to indoor use with flash :an AF540FGZ with an 18mm lens your flash range is going to be pretty abysmal no matter what you do, so I say it's a moot point on which one you get. at 10mm the difference between f/4 and f/3.5 is trivial. though at the ~20mm end the extra stop or so the f/3.5 version provides might come in handy.

[Laurentiu Cristofor]

While I don't have any direct experience with either of the versions of the 10-20, from what I read around, I'd go for the 4-5.6 version, because it's cheaper and the 3.5 does not appear to have other significant advantages besides the constant max aperture.

Also, I'm not sure if you've seen this, but it might make your decision harder:

8-16mm f/4-5.6 DC HSM

If I would be looking for a wide-angle zoom, I'd wait to see reviews of this lens.

[Ira]

While I don't have any direct experience with either of the versions of the 10-20, from what I read around, I'd go for the 4-5.6 version, because it's cheaper and the 3.5 does not appear to have other significant advantages besides the constant max aperture.

Also, I'm not sure if you've seen this, but it might make your decision harder:

8-16mm f/4-5.6 DC HSM

If I would be looking for a wide-angle zoom, I'd wait to see reviews of this lens.

Not for Pentax.

[Marc Sabatella]

Not yet, but they've announced it will be shortly.