[5ks]

In order of price and portability (lower -> higher)

DA*300+1.4 --> DFA 150-450 --> DA 560 --> Sigma 500 f/4.5 (used only)


(Note, I think some people reported vignetting with the DA*300+1.4 on the K-1)
I'm excluding some of the Sigma zooms as I don't think they would be better than the DFA150-450

I wonder how much (or disturbing) is the vignette in full frame when using DA* 300 with HD DA converter 1.4x?

-- I plan to invest in either DA*300 or DFA 150-450 next year. The converter I already have (and DA*60-250, unmodified for FF) . DFA 150-450 would certainly be more versatile but it is also about twice as heavy and expensive as DA*300.

[vijaykishan]

Nope, you have to evaluate the FOV column of the fist graph, so:
1 - the SMC pentax-FA* 645 300mm F4 ED [IF] has on a K-1 a FoV of 8,2°, to match this FoV on a 645 NII you have to use a 483mm.
2 - the SMC pentax-FA* 645 300mm F4 ED [IF] has on a 645 NII a FoV of 13,3°, to match this FoV on a K-1 you have to use a 186mm.

Then if you put a SMC pentax-FA* 645 300mm F4 ED [IF] on a K-1 you don't obtain a FoV of 5,3° like a 483mm on 135

This seems to run contratry to what I can remember . Let me do a small experiment when I get some time in the next few days. I will mount the FA* 645 300mm F4ED on the K1 (with a converter of course), focus on an distant object like a house/Tree of something - let's call this Frame-A. Keeping the same position I'll change the lens to a DA* 60-250 F4 and click a Frame at around 186mm (Frame-B) and another one at 250mm. I'll post the results on this thread to settle this one and for all.

[Sandy Hancock]

Don't bother with the DA*60-250. I have the DA* 300/4.0 and the FA*645 300/4.0 (and a 645 to K adaptor).

I'm willing to bet that on the K-1, at distant focus, I would barely be able to tell the two apart. 300mm is 300mm regardless of the sensor size.

[Andrea K]

This seems to run contratry to what I can remember . Let me do a small experiment when I get some time in the next few days. I will mount the FA* 645 300mm F4ED on the K1 (with a converter of course), focus on an distant object like a house/Tree of something - let's call this Frame-A. Keeping the same position I'll change the lens to a DA* 60-250 F4 and click a Frame at around 186mm (Frame-B) and another one at 250mm. I'll post the results on this thread to settle this one and for all.

If you think to obtain the same shot between Frame A and Frame B then please reread my previous post.

The test should be:
1- a shot with a 645N (or a 645D) and the 300mm
2- a shot with the K-1 and the 60-250 at 186mm (or 235 if you have a 645D)
3- a shot with the K-1 and the 60-250 at 250mm
4- a shot with the K-1 and the 645 300mm

1 and 2 will be equal, 3 and 4 almost equal with the 4 a little bit "zoomed"

[Lowell Goudge]

I will go back to the OP’s question and ignore the crop factor debate. Focal length is focal length. Period

To the OP there are a lot of things to get that range, but in new lenses there are only 3, the DFA150-450 zoom, the DA300/4 plus 1.4x Pentax TC(APSC only) and the DA560(which is likely out of your price range, but a great lens if you can swing it)

Used I would look to a Pentax FA300/2.8 or sigma 300/2.8 plus a sigma 1.4x or 2x TC, or a used sigma 500/4.5. These would likely push the top of your price range but would be really what you need

If you are going wild life, especially birds, you will spend the majority of your time at maximum focal length which is why I would recommend a prime over a zoom.

My path to wild life has gone through a long route to the DA560 which I looked at and compared over and over again to the Sigma 500/4.5 and the 300/2.8 largely because I already have a sigma 70-200/2.8 and both 1.4x and 2x TCs, but in the end I am glad in the choice I made. The autofocus of the DA560 is much more positive than a screw drive mechanism can deliver.

[bdery]

The 150-450mm is a fantastic lens, and one I would recommend without hesitation.

[vijaykishan]

Don't bother with the DA*60-250. I have the DA* 300/4.0 and the FA*645 300/4.0 (and a 645 to K adaptor).

I'm willing to bet that on the K-1, at distant focus, I would barely be able to tell the two apart. 300mm is 300mm regardless of the sensor size.

You are right, what you have offered would be a much better comparison. A frame from both lenses on the K1 would settle the debate - looking forward to it. I'm not betting, just willing to learn . thank you.


Focal lenght doesn't change - I agree; OTOH, How much of the image circle is the sensor/Film exposed to, IMHO determines the resultant FOV. AFAIK that is the very reason that 50mm 135 lens results in a narrower FOV on the crop sensor - is it not ?


Apologies that this might have become a split thread and might need to be taken elsewhere. At the same time, if we have solid evidence that the 645 300mm offers a narrower FOV on FF (135), then it would be legit option for people with K1.

[bertwert]

Apologies that this might have become a split thread and might need to be taken elsewhere. At the same time, if we have solid evidence that the 645 300mm offers a narrower FOV on FF (135), then it would be legit option for people with K1.

Lol, we certainly do not. The focal length is an optical property of the lens, absolutely nothing to do with sensor size. As people have said multiple times, 300mm is 300mm, doesn't matter if it's on a 1" sensor or a 645 sensor. All the smaller sensor does is crop the image. A 300mm designed for full frame with only project an image large enough to cover the full frame sensor - it would vignette on a 645 sensor, and a 645 designed lens wouldn't. Put both on a K-1 and you will have the same magnification on the image, no difference at all.

If you only have one format, and even if you have multiple, I suggest you stop thinking about equivalence and just sort of learn what each focal length corresponds to on your camera - but a 300mm is always a 300mm.

In short, the 645 300mm on full frame will offer the exact same FoV of the FF 300mm, but it is a cropped view of the 645 300mm on a 645 camera - which isn't really relevant to this thread at all.

Also, there's no reason to get a 645 lens if you're shooting full frame, especially tele, it will be larger, require adapters, etc etc.

[angerdan]

In short, the 645 300mm on full frame will offer the exact same FoV of the FF 300mm, but it is a cropped view of the 645 300mm on a 645 camera...

No, that's incorrect. The FoV of a 645 300mm on a K-1 will be ~468mm, because only 64% of the available diagonal FoV of the 645 Lens are used by the K-1.

So there's a crop-factor for the FoV of a 645 lens on a K-1 of ~1,56x.

[bertwert]

No, that's incorrect. The FoV of a 645 300mm on a K-1 will be ~468mm, because only 64% of the available diagonal FoV of the 645 Lens are used by the K-1.

So there's a crop-factor for the FoV of a 645 lens on a K-1 of ~1,56x.

You clearly missed the part of my post here:

The focal length is an optical property of the lens, absolutely nothing to do with sensor size.

The sensor size designation of a lens, be it 645, FF, APS-C is only to indicate the sensor size that the lens can cover.

The only equivalence you're seeing there, is a 300mm lens on a 35mm camera will offer the same field of view as a 483mm lens on a film 645 camera. A 300mm lens doesn't magically become longer because you're using it on a smaller sensor size.


Anyways, this has absolutely nothing to do with the OP's question. The question was the best telephoto lens to use on the K-1 of at least 400mm (note: longer than the 645 300mm lens which is irrelevant to this discussion) - the most popular recommendation to which is the 150-450, where I've seen many excellent images posted taken with it, and would recommend that to the OP.

[angerdan]

Anyways, this has absolutely nothing to do with the OP's question.
the most popular recommendation to which is the 150-450, where I've seen many excellent images posted taken with it, and would recommend that to the OP.

You're right.
But if there are wrong informations, they should be corrected.

If you think to obtain the same shot between Frame A and Frame B then please reread my previous post.

The test should be:
3- a shot with the K-1 and the 60-250 at 250mm
4- a shot with the K-1 and the 645 300mm

3 and 4 almost equal with the 4 a little bit "zoomed"

No, because the (diagonal) FoV of 250mm on 24x36mm Sensor size is 6.5°. With a 645 300mm on 645D / 645II the FoV is 10.5°/ 13.3°.

So the difference regarding FoV in your example is around factor 2x.

[bertwert]

But if there are wrong informations, they should be corrected.

Except you replied to my post:

In short, the 645 300mm on full frame will offer the exact same FoV of the FF 300mm, but it is a cropped view of the 645 300mm on a 645 camera...

By outrightly stating it's wrong:

No, that's incorrect.

You're correcting correct information with incorrect information!


This isn't constructive or relevant to the topic, and this is my last post about this, as I've realised I'm stubborn and have been reeled in.

[RICHARD L.]

The FoV of a 645 300mm on a K-1 will be ~468mm

False and totally ludicrous ! I sometimes use my 645 FA 400 mm f/5.6 with an adapter on my Pentax K1 (no automation whatsoever then) and a 400 mm FL is a 400 mm FL. The FF sensor simply intercepts the center of the aerial image produced by the lens. Please change the subject and come back to the question of the Original Poster.

[Andrea K]

But if there are wrong informations, they should be corrected.

True but enough is enough. Therefore I, that have a K-1, a 645 NII, an A* 300mm and a FA* 645 300mm so all of this isn't only theory but above all practice, stop here.
FoV Calculator already set at FF and 250mm to show that the diagonal FoV is 9,89°

[Driline]

Except you replied to my post:


By outrightly stating it's wrong:



You're correcting correct information with incorrect information!


This isn't constructive or relevant to the topic, and this is my last post about this, as I've realised I'm stubborn and have been reeled in.

My head is "spinning". Please make it stop