... finally went through and bought a Pentax K-5 II with a kit lens (the lens was for free actually). After almost 4 years of mingling with Micro Four Thirds I decided that I need to get back to my love of Pentax and Astrophotography. I was so tempted to go for Fujifilm for there unbeatable High ISO Performance but even with the sensor advancements of Micro Four Thirds and Samsung (NX1 is so good specked) and Sony's low pricing of A7 (even 1000 Euros in some places) they still lack one thing: Pentax O-GPS1. And how many small, portable, lightweight, good IQ, and under 300 Euros tracking telescopes do you know?
Now before I get the O-GPS1 I have to decide on a few lenses to use for astrophotography, and the general rule would be to go as fast as possible but that is one of the problems of Pentax K mount, there aren't many such lenses unfortunately.
At wide angle you only have the Samyang very good prices and IQ lenses (like the 10mm f 2.8, 14mm f 2.8, 16mm f 2) and one very expensive Pentax DA 14mm f 2.8. I would like to sacrifice 3 thirds if a stop of light for the Tamron 10-24mm f 3.5-4.5 / Sigma 10-20mm f 3.5 / Pentax 10-17mm f 3.5-4.5 or even more then one stop for the marvelous IQ Sigma 8-16mm f 4.5-5.6 (in thinking that sensors get better performance, lenses you own don't get change often enough to get wider or faster). Can't find a solution for the wide angle problem yet.
Now to a fast normal (for more panoramic shots deep space objects) I was thinking that 50mm f 1.4 would be enough but I do love the idea and the IQ of Sigma 18-35mm f 1.8 not only for speed but also I DO use the camera and lenses for OTHER stuff, like daylight shooting ? So maybe I will reserv that spot of an legacy lens (but I fear of bad coma optimization for there are not many legacy lenses with Aspherical elements to correct it, and it it where they are to close to modern and corrected lenses, like Sigma 50mm f 1.4).
... and to the biggest question so far. Deep space objects need FL ... and lot's of it (M33, M42, M43, Orion's Sword, Flame Nebula, Horsehead Nebula. etc). But speed would be needed to, to help to get longer shutter speeds or lower ISO usage. For cheap solution I was thinking of Tamron SP 70-200mm f 2.8, maybe use a teleconverter to get a bit more reach but not lose to much speed. I do find Sigma 70-200mm f 2.8 very well corrected for coma and not bad performance but a bit more heavy and more expensive. Pentax DA* 200mm f 2.8 is not very lightweight nor is it cheaper then Tamron to get a better solution, plus I would lose the 70 to 199mm part to. Would a standard zoom like the Pentax DA 55-300mm f 4-5.8 WR or Tamron / Sigma 70-300mm f 4-5.6 handle at there speed deep space objects (with the always recommended and needed image stacking).
I might try some "unorthodox" lenses, mostly for lunar imaging or even photographing some sun spots, like the Samyang (or equivelent on the market) 500mm f 8, 500mm f 6.3 Mirror, 800mm f 8 Mirror, 600-1300mm f 11 for there dirt cheap price and, possible, fun element.
I'm looking for some help some ideas, opinions. recommendation to get a few lenses for Wide Field Astrophotography and Deep Space Astrophotography within a 2500 Euro's budget (I will spend almost two year's worth of saving). I do feel a little concerned about the weight of the lenses (the reason I used Micro Four Thirds before) but if I have to sacrifice that to get from this:
... to this:
... then I will take it. Maybe one day I can afford two systems (still dreaming at Panasonic GX7 + Panasonic 12-35mm f 2.8 + Panasonic 35-100mm f 2.8 = 1KG of goodness).
Last edited by Blue; 09-30-2014 at 06:48 PM.