[maisz]

I'm looking between these two lenses and am looking for one that will best help me bring out Astrophotography pictures.

[luftfluss]

I'm looking between these two lenses and am looking for one that will best help me bring out Astrophotography pictures.

Well, the Penax 15-30 is full-frame while the Tamron 17-50/2.8 is for APS-C.

[maisz]

Well, the Penax 15-30 is full-frame while the Tamron 17-50/2.8 is for APS-C.

Which one works best with the Pentax K3

[luftfluss]

Which one works best with the Pentax K3

The Pentax 15-30 is much more expensive (and larger, heavier) than the Tamron. Due to the massive price disparity, it is odd to compare them IMO.

I owned the Tamron 17-50 and while sharp, build quality was just OK.

Lenstip has reviewed both the Tamron 17-50/2.8 and the Tamron 15-30, which the Pentax version is based on. Some of the Lenstip tests are pertinent for astro work.

https://www.lenstip.com/index.html?test=obiektywu&test_ob=18

https://www.lenstip.com/432.1-Lens_review-Tamron_SP_15-30_mm_f_2.8_Di_VC_USD_Introduction.html

[BigMackCam]

Which one works best with the Pentax K3

The D FA15-30 will work just fine on the K-3, the image quality is better than the Tamron 17-50, and it gives you 2mm more at the wide end. 2mm is a lot when you're talking about very wide angle. That said, it's a big and heavy lens, and it's not easy or cheap to fit filters to it. Arguably, it's overkill for the K-3... You'd be better off with the DA16-85, or - if constant f/2.8 aperture is a must - then the new DA*16-50 PLM. You're only losing 1mm off the wide end with either of those lenses. The 16-50, in particular, would be a fantastic choice. Or, if you're happy to lose yet another mm off the wide end and you're not concerned about weather resistance, the Tamron 17-50 f/2..8 and Sigma 17-50 f/2.8 HSM are both good lenses...

[cmohr]

For the K-3, aand Astro, the lens to get would not be the DFA15-30/f2.8 , but the HD DA*11-18/f2.8 , it is the same field of view on the APS-C as the 15-30 is on FF.

HD Pentax-DA* 11-18mm F2.8 ED DC AW Reviews - DA Zoom Lenses - Pentax Lens Reviews & Lens Database

[UncleVanya]

The DA* 11-18 is the more normal comparison lens to the D FA 15-30 since they both cover close to the same angles of view when the 15-30 is used on Full Frame cameras like the K-1 and the 11-18 is used on an APSC body like the K-3.

What lenses do you have now? What are you trying to photograph?

[mikesbike]

Which one works best with the Pentax K3

The DFA 15-30mm will offer no tele range on APS-C cameras, therefore not nearly as versatile as a 17-50mm lens, while on the FF K-1 it will serve as intended- a fast ultra-wide premium zoom lens. I have the Sigma 17-50mm f/2.8 EX DC HSM and I like it very much. A very nice, well-built, well-designed lens with sharp results. But Sigma has discontinued production in the Pentax mount. Now hard to find, but I believe I very recently saw one still for sale via Amazon, during my purchase of another unrelated item.

Now the ultimate in this range is the new Pentax DA* 16-50mm f/2.8 PLM lens reputed to have super-fast, accurate AF, which will AF during video. This lens also has excellent construction, including WR. However, all these advancements come at a high-price.

[beachgardener]

I have a 17-50 Tamron, nice images from it, very happy, but, it has some sort of plastic bush on the zoom internals, it gets stuck, it sort of slips over the bush, not sure if there is a permanent fix. I would buy another though, I like it that much.

[maisz]

The DA* 11-18 is the more normal comparison lens to the D FA 15-30 since they both cover close to the same angles of view when the 15-30 is used on Full Frame cameras like the K-1 and the 11-18 is used on an APSC body like the K-3.

What lenses do you have now? What are you trying to photograph?

I have an HD Pentax-DA 1:2.8 40 mm Limited Pancake lens, a Sigma 18-300 1:3.5-6.3 Pentax mount, an 18-55 Kit lens, and a Tamron AF 28-75 F/2.8 (IF) Macro Pentax mount. I am trying to take pictures of the Milkyway and constellations. I currently take pictures of Sun Rises and Run Sets, Clouds, Lightning, Moon, and Stars.

[UncleVanya]

I have an HD Pentax-DA 1:2.8 40 mm Limited Pancake lens, a Sigma 18-300 1:3.5-6.3 Pentax mount, an 18-55 Kit lens, and a Tamron AF 28-75 F/2.8 (IF) Macro Pentax mount. I am trying to take pictures of the Milkyway and constellations. I currently take pictures of Sun Rises and Run Sets, Clouds, Lightning, Moon, and Stars.

You should read this thread. You can use your existing lenses as a start.

Pentax Astrotracer Milky Way Photography - PentaxForums.com