[Jtax]

I ordered it from mpb, hopefully it will arrive within the next week. Almost got a brand new one with a shutter count of 700, but it was sold as I was checking out . So I was forced to settle for one with a shutter at 21,000. I'm counting on this not being a problem, because a ~$400 purchase is a lot for me. I also grabbed an 18-55mm f/3.5-5.6 AL II lens with it.

I plan on doing almost exclusively nature/astrophotography with it, with perhaps some night shots of the city as well. My budget is tight at the moment, so I'm looking for some inexpensive lenses (under $100 used) that offer a lot of bang for the buck. Thanks in advance!

[ismaelg]

Hello,

If you don't mind manual focus (which you will most likely need for astro anyway) a fast 50 like the M 50 f1.7 is great. Quite possibly my all time favorite lens.

Thanks,

[jatrax]

So I was forced to settle for one with a shutter at 21,000.

Think of it as mileage. 21,000 is just barely broke in if it has been cared for.

As to lenses:
For astro (assuming that is landscape astro and not deep sky) then the Samyang 16 f/2 is highly recommended. Here is a link to a list of lenses recommended for astro: Lonely Speck’s Ultimate List of Best Astrophotography Lenses – Lonely Speck

Note that one of the recommendations is the Tamron 15-30 f/2.8 which is the Pentax DFA 15-30

For landscape assuming you are OK with manual focus then there are lots of Pentax lenses available. Try most any of the Pentax-A primes.

I would strongly recommend the Pentax DA 16-85 but I think that is going to be out of your budget.

[bladerunner6]

I ordered it from mpb, hopefully it will arrive within the next week. Almost got a brand new one with a shutter count of 700, but it was sold as I was checking out . So I was forced to settle for one with a shutter at 21,000. I'm counting on this not being a problem, because a ~$400 purchase is a lot for me. I also grabbed an 18-55mm f/3.5-5.6 AL II lens with it.

I plan on doing almost exclusively nature/astrophotography with it, with perhaps some night shots of the city as well. My budget is tight at the moment, so I'm looking for some inexpensive lenses (under $100 used) that offer a lot of bang for the buck. Thanks in advance!

The 50mm 1.8 is about $100 new and the 35mm 2.4 should be available at that price.

Those are the first two that come to mind.

[aslyfox]

welcome to the forums

you will find friendly members and a lot of knowledge here

do you have the manual

http://www.ricoh-imaging.co.jp/english/support/man-pdf/k-3.pdf

check here for owners' review and the in depth review

Pentax K-3 - Pentax K-mount DSLRs - Pentax Camera Reviews and Specifications

if you are willing to go with " experienced " lenses, don't overlook the forums' marketplace which can be sorted by country -

The Pentax Marketplace | Buy & Sell Pentax Cameras and Lenses (United States) - PentaxForums.com

and check under " lenses " above for reviews of various lenses

[FozzFoster]

Here is my suggestion:
Sell the 18-55 and buy an 18-135. Neither are perfect, but the extra range and image quality will be appreciated.
I have done astro with the 18-135, and while it's not perfect for astro it can deliver good results:

[PocketPixels]

If you're on a budget, you can stay with the kit lens for a while. I went years with just my 18–55 DA and the 10–17 Fish-Eye.

There are many, many quality used lenses on eBay, mpb, and here in the "for sale" section, but if you're really on a budget, the best thing to do may be nothing. It's a good kit lens on a great camera. You'll do fine! Put it on a tripod and learn what kind of night shots you can already get. Then learn what kind of night shots you can't already get, and then buy a lens that will let you get those shots, too.

Welcome to the Pentax forums!

[Paul the Sunman]

The "plastic fantastic" primes are great values: DA 50 f/1.8 ($97 new at B&H) and DA 35 f/2.4 ($117 new).

[aslyfox]

. . . I plan on doing almost exclusively nature/astrophotography with it, with perhaps some night shots of the city as well. . . .

perhaps this series of articles ( 6 in total ) might be worth reviewing:

Astrophotography Part 1 of 6: Planning the Shoot
Getting ready to take pictures of the night sky
By K David in Articles and Tips on Mar 12, 2015

Read more at: Astrophotography Part 1 of 6: Planning the Shoot - Articles and Tips | PentaxForums.com

[DWS1]

I like the DA 16-85mm for almost everything, including astro.

[UncleVanya]

I like the 18-135 better than the kit lens. However the advice above is true. You can make the kit lens work. Grab a DA or DAL 55-300 (the old versions) and maybe a da 35 f2.4 and you are set for quite a while.

[Des]

Welcome to PF!

Grab a DA or DAL 55-300 (the old versions)

+1. Assuming the preference for "nature photography" includes wildlife, a telephoto lens is required. At around $US100-150, these two provide great bang for buck:
SMC Pentax-DA L 55-300mm F4-5.8 ED Reviews - DA L Zoom Lenses - Pentax Lens Reviews & Lens Database
SMC Pentax-DA 55-300mm F4-5.8 ED Reviews - DA Zoom Lenses - Pentax Lens Reviews & Lens Database
The DA-L should be cheaper as it has a plastic (rather than metal) mount and lacks QuickShift (the ability to focus manually while in autofocus mode), but neither of these should be a dealbreaker. The DA-L wasn't supplied with a hood, but cheap knock-offs are available from ebay. The main thing is to look for one (whether DA or DA-L) in good condition.

[heinamj]

Try most any of the Pentax-A primes.

I agree, and the KA mount will give you access to all of the features of the K3 except the motor to focus the lens. You'll be able to use Hyper Program and Hyper Manual with a fully image stabilized lens thanks to IBIS.

Thankfully most of the Samyang lenses as KA mounts too. If you could ever save up the budget for it, the Samyang 135mm F2.0 ED UMC is one of the most amazing astrophotography lenses out there...

[aslyfox]

these can be useful charts

Pentax K-Mount Lens Series Explained: The differences between various Pentax lens series

In a nutshell
There are several series of Pentax K-mount lenses; the ones currently being produced include the DA (digital), DA L (cheap digital kit), D FA (full-frame, digital optimized), and FA (full-frame) series. While all Pentax K-mount lenses ever produced are compatible with all current Pentax DSLRs (in some cases with restrictions in that not all exposure modes of the camera are supported by old lenses), there are significant differences between each lens series and each has different features. Furthermore some of the newer lenses do not work with older cameras. We'll be exploring the differences between the various K-mount series lenses in this article.

Pentax K-Mount Lenses Explained: The differences between various Pentax lens series

_________________

Pentax K-mount Lens Compatibility Chart
Copyright 2006-2020 Mosphotos.com. All rights reserved.

Pentax bayonet lenses labeled "SMC Pentax" are referred to as "K" lenses in the table below. Other Pentax bayonet lenses have the lens designation as a part of their name as in "SMC Pentax-FA".
Note that "star" lenses work like their "non-star" counterparts unless they are singled out in the table below. So for compatibility of a DA* lens which is not singled out, look under DA lenses, etc.
Exceptions: FA and F "soft" lenses behave like M lenses in terms of metering.

The Pentax K-mount Camera Lens Compatibility Chart

[rr1736]

21000 is almost new mine has over 200,000 and it just keeps on going a great camera