[jocelys1]

Hi,

I've been a user of the A* 300mm for a while with very satisfying results, both in IQ and color. Recently though the drawbacks when it comes to distance is quite clear. I'm thinking of investing in the 150-450 and wanted advise on whether the results will improve in any way.

Wildlife in India is rarely less than 50ft away and 150-300 ft is the average. The 300mm has done a stellar job upto around 150ft but not more.

Beyond that, the images don't retain the sharpness as you zoom in. Is this better with the 150-450 - better coating, resolution ? I'm using the K5 and expect to continue with the same body.

Any advise or info would be helpful. Thanks.

[tduell]

I can't make the comparison for you, but I do shoot with the 150-450 + 1.4TC a lot with the K3-II, and find the quality is excellent, and most of the time I'm shooting wide open.

Cheers,
Terry

[MJKoski]

Unless the A-version is different compared to M-version I would not hesitate getting thqt zoom. I found the IQ of M* 300mm to be exceptionally poor on K-1. Much worse than samples I have seen from 150-450 on K-1.

[bdery]

I've used both. The A*300 is superb, well balanced, well made, plenty sharp.

The 150-450 is at least as good in all respects except max aperture and size. If you can afford it, I think it will be a good upgrade.

[onlineflyer]

If funds are tight, get a F 1.7x AF adapter, that will give you more reach than the 150-450mm on the long end. That's what I use, it's affordable, light weight, and it gives you both extended range and af. If you can afford it, go for the 150-450mm. It's more versatile, has better IQ and a tripod mount.

[jocelys1]

Thanks for the advise guys. Positive so far.

The A*300 is a beautiful lens. I've enjoyed it a lot. I'm trying to get a little more reach, thats why the 150-450. Question is, will this lens perform at 450mm, atleast as good as the 300mm is at the shorter distances ?

[MJKoski]

Coatings of the M* 300mm are like this (no filters, nothing in front of the glass):



There is no way the modern zoom will produce something like that. And, if the A* is optically the same then I suggest getting FA 300/4.5 or the zoom.

[fwcetus]

Coatings of the M* 300mm are like this (no filters, nothing in front of the glass):
There is no way the modern zoom will produce something like that. And, if the A* is optically the same then I suggest getting FA 300/4.5 or the zoom.

1. The original poster could have said exactly which "A* 300" he/she was referring to. It seems, from at least some of the replies that at least some others seem to be assuming he/she meant the A* 300/4 and not the A* 300/2.8, but there is of course a difference between the two "A* 300" lenses.

2. As for the M* 300/4 to A* 300/4 comparison, the two lenses ~seem~ to be optically virtually "identical" (in that their optical diagrams seem to be basically the same), but that is not to say that the coatings are the same (or, perhaps less likely, that the glass itself may have been tweaked in the A*). I have not owned either the M* 300/4 or the A* 300/4 in quite a few years now, but I seem to remember that the M* had an "orangey" coatings appearance, while the A* had a "greenish" coatings appearance, so that the two lenses may not have rendered MJKoski's sample subject the same way. (Just sayin'...)

3. I have no experience with any "150-450", but, FWIW, my experience is that, for the smaller 300mm primes, either the F* 300/4.5, or the FA* 300/4.5, or the DA* 300/4 would each be a significant improvement over either the M* 300/4 or the A* 300/4.

[gaweidert]

I have both the Pentax A* 300 f4.0 and the D FA 150-450. I am seeing a lot of purple fringe with the 300mm lens on my K1. Changing aperture doesn't seem to help much either. I have used the 300mm for over 25 years and I liked it a lot, but to me the 150-450 lens simply rocks. It is big and heavy, but I do use it hand held quite a bit without much trouble. Share reduction rocks too.

[MJKoski]

It may well be the coatings, M* indeed has orange like color in them. And sure, F(A) 300/4.5 or DA 300/4 cannot be any worse but likely a lot better and not only for coating part.

[jocelys1]

Fred, good point you made there, the lens is the A*300@f4.

Gaweidert, I've seen the same purple fringing especially with an early morning sun. How is the 150-450 in terms of picking up objects at a distance, something the 300 starts failing at really long distances ?

[normhead]

If funds are tight, get a F 1.7x AF adapter, that will give you more reach than the 150-450mm on the long end. That's what I use, it's affordable, light weight, and it gives you both extended range and af. If you can afford it, go for the 150-450mm. It's more versatile, has better IQ and a tripod mount.

That's what I'd do. Use the ƒ1.7x with a Tamron SP AF 300, and it works quite well.

It gets me to 510mm ƒ4.5. But the 150-450 is a quite nice lens as well. A zoom is always more usefull, but a little more reach and faster aperture are also worth having.With the A*300 you also have the chance to stack TCs. This works great with my DA*200 but not with my Tamorn 300. If you could stay the 1.4 and 1.7 that would get you out to almost 700mm, at ƒ6.3. If it worked you'd be leaving the 150-450 in the dust.

IN any case, the F 1.7 x AF adapter was designed to work with lenses like the A*300. And it even gets you limited AF, for your MF lens, for a fraction the cost of the DFA 150-450.

But, if the A*300 purple fringes as reported above, the 1.7 is going to make it a lot worse.

[jocelys1]

I had a bad experience with 1.7x and sold it. On the A*300, while I will get the reach, the 1.7x converter will not help with the resolution at the distance, which is why I thought the 150-450 might do a better job. Does that make any sense ?

[MJKoski]

I have found extenders to be really usable with supertelephoto lenses like 200/2, 300/2.8, 500/4 and such. Their base IQ is so high usually that 200/2 cropped to 400mm equivalent perspective is usually better than standard 200/2.8 with TCs.

Adding a TC to "cheap" options means only trouble.

[normhead]

I had a bad experience with 1.7x and sold it. On the A*300, while I will get the reach, the 1.7x converter will not help with the resolution at the distance, which is why I thought the 150-450 might do a better job. Does that make any sense ?

If that's what happened, then it doesn't matter if it makes any sense, it just is what it it. My two DA* lenses works well with the 1.7, as do my Tamorn 90, Sigma 70, etc. Every high quality lens I've tried it with. So it's kind of surprising id didn't work with the A*300. But I don't know the lens,

Understanding folks saying a TC doesn't ad more detail. - PentaxForums.com

The biggest problem I've had getting detail with the Tamron 300 2.8 is lens movement. It's rare you have a chance to completely lock your tripod, and use the two second timer. The 1.7 exaggerates lens movement, 1.7x as well as increasing image size.

As to whether or not the 150-450 will do better, that would require some testing by someone who has both to work out what the parameters around that would be.

I guess the things buyer, you know the A*300 and 1,7 won't do what you want, the only question is will the 150-450? You should rent one. Or if your serious, find a company to buy from who will let you return it if it doesn't do what you want.

I'm not sure I've ever seen an image taken with this lens, so I don't even have a post to point you to. On the forum the A*300 is rated a 10, but we have no idea what that means except everyone who owned it thought it was an exceptional lens (all three of them) . Would they think that if they owned a 150-450? Who knows?

One did post images that are no longer available taken with the 1.7, so how bad could it have been?

I recently did som time with the A-400 and the 1.7. it would be hard to comprehend how the A*300 would be worse.
https://www.pentaxforums.com/forums/122-lens-clubs/55946-300mm-plus-lens-clu...ml#post3962692

Looking at these reviews from 2007 and 2008, I wish they could be redone by folks who have used more modern lenses. we know they were good 10 years ago, but over the last 10 years, the whole heavily corrected edge to edge sharp craze has really taken hold.