[DeadJohn]

I am thinking about moving on from my K3 and going full frame with the K1. ... I shoot quite a bit of kids’ sports so I definitely need a long lens for that. ...

I like my K-1 a lot but it doesn't specialize in action photography. You'll be able to get sports photos with it, but Pentax APS-C models at half the price can achieve similar results.

IMO the main reason to get a K-1 is for landscape and low-light photography. That's where it excels. It's also very good at portraits, macro, architecture, and general photography.

[surfar]

I am thinking about moving on from my K3 and going full frame with the K1. Which of my lenses would I no longer be able to use if I decide on the full frame?
55-300
18-135
18-55
50-200
50 f1.8
35 f2.4
Sigma 10-20
Sigma18-35 f1.8

OK, i own all these bar the 18-35 Siggy.

Crop mode is fine for all...1:1 all except 18-135(highly disappointing)..

In FF, the primes are fine..zooms ya just gota play around with...they all work at different places along their focal lengths.Theres a thread about DA lenses on FF...have a look at that.

With that range of lenses, you have a good starting point...However,DFA 28-105 and 70-200 are a pretty good investment.

[clackers]

OK, i own all these bar the 18-35 Siggy.

Crop mode is fine for all...1:1 all except 18-135(highly disappointing)..

In FF, the primes are fine..zooms ya just gota play around with...they all work at different places along their focal lengths.Theres a thread about DA lenses on FF...have a look at that.

With that range of lenses, you have a good starting point...However,DFA 28-105 and 70-200 are a pretty good investment.

+1

Wise words, Surfar!

[jimr-pdx]

Good to know. I have a few good primes and tolerable 36×24 zooms but would prefer shooting squares over pre-cropped 3:2 mode. But hey, I'm odd enough to consider shooting sub-36Mpx uncropped for times i don't want to repaper a wall in my home. ?

[Kozlok]

I’m going to disagree with your first impulse. You are much better off taking your money and getting better lenses and staying APS-C.

[SCGushue]

I’m going to disagree with your first impulse. You are much better off taking your money and getting better lenses and staying APS-C.

I don't think I would disagree with you. Alex has a very decent collection of lenses and an excellent body in the K3. Unless there is a specific reason to go FF why jump? I have cropped bodies thru the K5 iteration, and the 645z. I pondered long and hard before deciding on getting the K1m2. In reality there are many advantages to the crop bodies and lenses and I don't see them going the way of the dinosaurs any time soon.

If the OP is just itchin' to spend a lot of dough on the fantastic K1 go for it. But be prepared to spend a considerable sum for high end lenses because that is what it will take to make images on that body worth buying it in the first place.

Best wishes to Alex on his decision.

[Eyewanders]

OK, i own all these bar the 18-35 Siggy.

Crop mode is fine for all...1:1 all except 18-135(highly disappointing)..

In FF, the primes are fine..zooms ya just gota play around with...they all work at different places along their focal lengths.Theres a thread about DA lenses on FF...have a look at that.

With that range of lenses, you have a good starting point...However,DFA 28-105 and 70-200 are a pretty good investment.

+2 - this is what I was trying to say, but here much more concisely.

---------- Post added 03-18-18 at 09:13 AM ----------

But be prepared to spend a considerable sum for high end lenses because that is what it will take to make images on that body worth buying it in the first place.

Hmmmm... only if one wants all the modern niceties of SDM and modern coatings, etc.. The K1 is just a camera and stunning images can be created using legacy FA and older glass if your'e willing to give up AF, use an ap-ring, and such.

[Igor123]

This might be helpful for how pentax da lenses perform on FF:
DA lenses on Full Frame: Test Shots thread - PentaxForums.com

I think many of the suggestions seem not to consider financials =)...as some say, keep it all and upgrade bit by bit after you've tried them on.

I have the 35 and it's great in ff mode on the K1, so I've heard about the 50. For longer I can recommend the tamron 70-200 2.8, its fast sharp and cheap with good build quality. Even longer and it starts getting more expensive but most of the 300 pentax primes are nice, pick one that suits the budget =), and a good TC for longer, the 400s aren't quite there IMO ...maybe the 400/600 2.8s are good but they are huge in size and price..I haven't tried any of them).

As for wider I don't have anything good to suggest within reasonable price...perhaps stick with the 18-35 in crop mode there for now? (If it covers 1;1 maybe that's about 14mm and good enough?)

Sell the rest =) (except if you need WR...then perhaps the suggested 28-105 is a good way to go)

[aslyfox]

You can use them all in crop mode, for sure.

You know about these, right ?: Pentax Lenses - Pentax Lens Reviews & Lens Database and Pentax Lenses by Sigma, Tamron, Zeiss, and more - Reviews and Specification Database - Pentax Lens Review Database

It may be that the 50 will work on FF w/o issues.

But, I would encourage you to slowly build up a group of FF lenses. . . . The 100 macro WR is great, . . . Don't hesitate to look into the used market. . . .

if you are looking into the " experienced " lens market

1 don't forget to look at the Forum's market place

2 regarding the Pentax 100mm macro F2.8 " family "

the same optical glass is shared by the F, FA, D FA ( non WR ) and D FA WR lenses

each " member " will sell at different levels if you can find them

check the In Depth Review of the D FA 100mm Macro F2.8 WR for confirmation

______________________________

remember that lenses developed in the Pentax 35 mm SLR " film " era were developed for the full frame sensor size you find in the K 1

this link shows the differences between each of the various Pentax lens " families " :



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

[ihasa]

I think the DA35 works on FF as well as the DA50mm. I've seen good reports of it on FF and have used it on my film cameras - it's lovely.

There's a bit of duplication with all those zooms. One approach would be to 'clean house' and start afresh on the K1, buying only what you really use and need. Perhaps a good f2.8 normal zoom lens (The Tamron 28-70mm is said to be decent enough) and a longer zoom that would replace your 50-200mm. I presume you got the Sigma 18-35 for shallow dof and good results in low light; well you'll be able to get that easily on FF.

[allexinwonderland]

I have a new 24-70 waiting for me. My plan for a while has been to get rid of the 50-200 and possibly the 18-55. I use my 55-300 all the time during baseball and softball season. The Sigma 18-35 is my favorite lens. I think I’ve come to my senses and decided to stick with the K3 for a while longer.

[texandrews]

I have a new 24-70 waiting for me. My plan for a while has been to get rid of the 50-200 and possibly the 18-55. I use my 55-300 all the time during baseball and softball season. The Sigma 18-35 is my favorite lens. I think I’ve come to my senses and decided to stick with the K3 for a while longer.

Yes, I think maybe you are better off, given your stated purposes and uses. Mine are pretty much the 180 degree opposite of yours.

[sylvainp]

The d fa 24-70mm f2.8 is my most used lens on my k1. I almost forgot about my primes since I got it. Fantastic lens for the price.

[allexinwonderland]

The d fa 24-70mm f2.8 is my most used lens on my k1. I almost forgot about my primes since I got it. Fantastic lens for the price.

I’ve rented the sigma once and the Pentax 24-70 twice. With the excellent deal I figured it was time to put it in my bag permanently.

[gaweidert]

How would the 55-300 etc work in 1:1 square mode?

No problem at all. It is a close to being a FF lens. I have the previous version. Not a bad little lens at all.