[MJ43]

There seem to be different experiences with the 55-300 PLM which I think must be down to variation in lenses. I like the 55-300 but for me it only works in a small window above 200mm and whatever I do is soft at 300, so much so that I bought a DA*60-250. The DA* is great but weighs a ton (by comparison with the PLM) and is slower at focusing, the loss in length is easily made up by IQ the downside is I miss more images (motorsport) as focus isn't as fast.

[SFX]

There is only 1 option for the K1 and that is the not cheap and not light but excellent (AF and sharpness) 150-450 mm. To be used with a monopod. No problem at all.

[wadge22]

In my opinion the best options are: the 60-250; a 70-200’ish lens; or the Sigma 100-400/4. All of these can be paired with a third party autofocus 1.4x TC to get you additional range. None are “cheap”, portability is debatable, but optical quality should be very good.

Just a note: the Sigma is 100-300 f4. They make a 100-400 f5.6-6.3 for other mounts, and they once made a few versions of 120-400 f4.5-5.6 and 135-400 4.5-5.6 lenses for Pentax that might be available used, but never a 100-400 f4 for anyone. Although that would be really nice if they did.


For OPs question, others have given all of these answers, but I'll compile it and give links:

Pentax 150-450 is probably the way to go, but it's out of your price range.
The Sigma 100-300 would be good, but it's hard to find.
You could look for the Sigma 120-400 or 135-400, or Tokina 80-400.
There are several of what people call the Bigma... 50-500, or 150-500, or 170-500
There are a few old Pentax 100-300s, and also 80-320, and also third party of such lenses, but they may not be top optical performers.
Or give up on zoom, and go for one of the stellar 300 f4 options from Pentax.
Or give up a little length and get the 60-250, which does require a little modification to be perfect on FF.

[MikeNArk]

Just a note: the Sigma is 100-300 f4. They make a 100-400 f5.6-6.3 for other mounts, and they once made a few versions of 120-400 f4.5-5.6 and 135-400 4.5-5.6 lenses for Pentax that might be available used, but never a 100-400 f4 for anyone. Although that would be really nice if they did.


For OPs question, others have given all of these answers, but I'll compile it and give links:

Pentax 150-450 is probably the way to go, but it's out of your price range.
The Sigma 100-300 would be good, but it's hard to find.
You could look for the Sigma 120-400 or 135-400, or Tokina 80-400.
There are several of what people call the Bigma... 50-500, or 150-500, or 170-500
There are a few old Pentax 100-300s, and also 80-320, and also third party of such lenses, but they may not be top optical performers.
Or give up on zoom, and go for one of the stellar 300 f4 options from Pentax.
Or give up a little length and get the 60-250, which does require a little modification to be perfect on FF.

I have the Sigma 135-400 APO lens and like the results that I get from it on the KP. Since I don't have a K-1, I don't know how it would perform on it. It's probably the most reasonably priced of that group of Sigma lens

[jddwoods]

Just a note: the Sigma is 100-300 f4. They make a 100-400 f5.6-6.3 for other mounts, and they once made a few versions of 120-400 f4.5-5.6 and 135-400 4.5-5.6 lenses for Pentax that might be available used, but never a 100-400 f4 for anyone. Although that would be really nice if they did.


For OPs question, others have given all of these answers, but I'll compile it and give links:

Pentax 150-450 is probably the way to go, but it's out of your price range.
The Sigma 100-300 would be good, but it's hard to find.
You could look for the Sigma 120-400 or 135-400, or Tokina 80-400.
There are several of what people call the Bigma... 50-500, or 150-500, or 170-500
There are a few old Pentax 100-300s, and also 80-320, and also third party of such lenses, but they may not be top optical performers.
Or give up on zoom, and go for one of the stellar 300 f4 options from Pentax.
Or give up a little length and get the 60-250, which does require a little modification to be perfect on FF.

Or give up on zoom, and go for one of the stellar 300 f4 options from Pentax.

This would be my recommendation. DA* 300. I have it and the 55-300 PLM. While I feel the 55-300 PLM is quite good up to about 270mm ( where it is still f5.6 or 5.8 ) it is not as sharp as the DA* 300 prime at 300mm, nor should you expect it to be. That is the reason for having a prime. Also I have the 1.4 TC and that extends the 300mm prime to 420 mm. Autofocus with my K-3 is not especially fast but it is good enough for photographing birds which is what I mostly use it for. Plus the in lens motor is quieter than any of the older FA zooms screwdrive.

[UncleVanya]

Just a note: the Sigma is 100-300 f4.

Typo. Fixed. Thanks for the catch.

[photogem]

Sounds like my issue as shooting similar targets (airplanes, birds).

The PLM on my KP is very good for birds (handheld, no tripod)
In very good light even some success with the DA AF Rear Converter 1.4x AW
But never tried it on my K-1.


I think there is either a problem with your lens or it is a question of technique.

[weverka]

The SMC Pentax-DA* 300mm F4 ED is crisp. And don't let the name fool you, it should have been labeled DFA.
I have also used it with the 1.7x teleconverter with great results.
SMC Pentax-DA* 300mm F4 ED [IF] SDM Reviews - DA Prime Lenses - Pentax Lens Reviews & Lens Database
SMC Pentax-F 1.7x AF Adapter Reviews - Pentax K-mount Teleconverters and Adapters - Pentax Lens Reviews & Lens Database

[rvandenbrink]

As far as "55-300 PLM is soft", it just plain is not (at least not my copy). Even fully racked out and with a 1.4x converter I'm usually good down to ~1/320 or sometimes even lower shutter speed (depends on the day), though using a tripod or something sturdy to brace against is always a good thing at longer lengths.
If you've got consistent softness issues, I'd do a set of "side by side" test shots (at F8 or 11) with and without a tripod. If after that you still see that there's a lens issue (ie - the tripod shots are not good) you might be able to calibrate to fix it.

[cdw2000]

Like others said, either you have a bad copy of the 55-300 PLM or there is a technique issue. I used the 55-300mm PLM at an airshow last fall and all the photos were tack sharp, unless I mis-focused or made some other error. There are also plenty example of shots with this lens here:

https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/365761-hd-...what-cant.html

[jslifoaw]

Unless it's a sub-par specimen, the 55-300 PLM should be a great performer on any DSLR it is compatible with. Technique becomes more important since zooming in increases shake and you also lose some light.

It will not be as good as either the DA*300 or DFA150-450 (nor should anybody expect it to be), but it isn't that far off. The advantages of those two lenses are primarily build quality (incl AW) and wider apertures with excellent image quality while the 55-300 has the widest zoom range (almost 5.5x), smallest size/lowest weight, fastest AF, and lowest cost.

[mlines]

Like others said, either you have a bad copy of the 55-300 PLM or there is a technique issue. I used the 55-300mm PLM at an airshow last fall and all the photos were tack sharp, unless I mis-focused or made some other error. There are also plenty example of shots with this lens here:

HD Pentax-DA 55-300mm F4.5-6.3 ED PLM WR RE - Show us what it can do, what it CAN'T! - PentaxForums.com

I have looked through that link and I get similar results to "Jersey" posting in that thread around page 79 who also commented here. Perhaps it is just not suitable in the way I want to use it. Yes if I work hard on a shot ie, a flowers close up with lots of time etc it is ok its more the "walkabout" telephoto that lots of people describe that escapes me

[rvandenbrink]

Ah, if things work OK on a tripod you likely don’t need to calibrate, and if you have shots where nothing is in focus it’s usually an unsteady hand, and at that focal length that’s pretty common. Try increasing your shutter speed, or re-assess your hand positions and grip? - when shooting you (ideally) shouldn’t see much movement in the viewfinder.

Or you might just need a tripod when you get to that focal length - no shame in that!

I just had a thought - you do have SR on correct? That would explain the situation just as well, I accidentally turned SR off a couple of days back, and I really needed it (shooting an osprey at ~400mm). It took a trip to the manual to figure out what I had done and reverse it!

[j0n4hpk]

I used to have a Tamron AF 28-300mm f/3.5-6.3 XR Di LD Aspherical (IF) Macro Ultra Zoom Lens for Pentax Digital SLR Cameras (Model A061P) and most of my results at 300mm (around 450mm equivalent on my APS-C DSLR camera body) were satisfying, although with a bit of pincushion distortion, notable only if subjects were distant cityscapes. If your subjects are human or nature, you can give it a try on the K-1.

[photogem]

This thread doesn't belong here into the K-70 section but into the K1 section!