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10-16-2018, 06:11 AM   #16
normhead's Avatar

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Im using my Tamron SP AF 300 2.8 LD [IF] with the Pentax F 1.7 AF adapter to give me 510 ƒ4.5 at 6 pounds.

The A*300 2.8 would be awesome with that. My biggest reason for wanting ƒ2.8 is you still get nice sharp crisp AF even with a TC.

That being said, I don't often carry the lens. It's a second day kind of lens in the bush. If I find something and I think I might go back, I'll carry the 300 2.8, straight there and straight back. I don't actually wander with it. Much of the time it's in the back of the car waiting for something near the road.

There are a few opinions above I'd just completely disregard.

Even with long lenses you get lots of subject isolation at ƒ5.6 in close for depth of field I usually shoot at ƒ5.6 or ƒ8. The big advantage to a faster lens is more light for the AF system. For fast subjects that can make a huge difference.

I haven't ever used a 150-450 so I'm at a loss there. For hiking, I prefer the 60-250 or 200 2.8 with a TC in the bag if needed. I honestly don't know if I'd use it much or not. My DA*60-250 gives me 350 ƒ5.6. With the 1.7x 425mm ƒ6.3.

As a general rule I use long slow combinations reluctant;y. I however do muse from time to time at the possibility of selling the 60-250 and Tamron 300 and getting a 150-450. On a full frame 150-450 is the equivalent of 100-300. That's really not that useful for birds, but should be a great wildlife lens.

Sorry, I can't be of more help.But this really is a matter of prefereence. It can be hard to find the subject with a fixed focus lens.

The Tamron 300 with a 2x TC on it.This is actually 600mm ƒ8, the Tamron TC doesn't directly record the ƒ stop and focal length in the viewfinder.

The 300 2.8s have a lot of resolution to spare for TC use.

Here's the 300 with the 1.7x

A closer look says it's a little sharper than with the 2X, but I really need Pentax to come out with the 2x TC. I'm not convinced the Tamron optical quality is anything to write home about. SO 300 2.8 isn't really a popular choice over the 150-450. But I really can't imagine having the 150-450 without the 300 2.8.

I'd like to have it as a walk around for the K-1, but the 60-250 with the 1.4 does just fine. And I don't know that I'll ever own a lens that heavy again. One beast is enough. The 18-135 and DA*60-250 with the TCs provide lots of reach for hiking in a nice lightweight package. And if it's a walk over 3 miles, I'll trade the DA*200 for the 60-250 to save weight.

Unless you have set up where you are not going to be moving much, bag lenses just aren't practical. AT 2000 grams the 150-450 is twice the weight of my 60-250, 3 times the weight of my DA*200 2.8, and I've had days when my 60-250 was causing me pain by the end of a 20 mile hike. The biggest factor is not the lens characteristics, but how you plan to use it. Imagine carrying 5 pound bag of sugar with you where ever you go. You'll start to get the idea

My Tamron 300 2.8 is 6 pounds, and it would be the first to go if I stared welling off lenses. Not because I don't like it's images, I prefer them, just because based on current use, my other two telephotos get used more.

Out on a hike with the DA*60-250 and 1.4 TC, hand held. (I should have used a tripod.) I might have a better image with the 300, but , it wasn't there so it's moot. And the 60-250 and 1.4 TC on the K-3 gives me more reach than the 150-450 on a K-1, for a fraction the weight.

Last edited by normhead; 10-16-2018 at 06:31 AM.
10-23-2018, 11:15 PM   #17

Join Date: Jul 2011
Posts: 1,774
The long tele debate is getting lame. Sold my Pentax A600 and DA300 this year. DFA150-450 would be an option, but Pentax forgot to present APS-C camera news, TC, .... DA560 is rediculously long. Old, used glass is overpriced. I am waiting to get a hand on a friends D500 to open up all options, new and used. If Pentax has a hidden agenda DFA300 as well as a normal sized 500+ will be on it. Did I mention FF TC. An APS-C camera makes for a nice TC.
Yes you can get very sharp images with manual lenses and older A/FA designs are quite OK, but these lenses are not the future.
10-10-2019, 01:54 PM   #18
angerdan's Avatar

Join Date: Feb 2015
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QuoteOriginally posted by zapp Quote
Did I mention FF TC. An APS-C camera makes for a nice TC.
Yes you can get very sharp images with manual lenses and older A/FA designs are quite OK, but these lenses are not the future.
The FF TC is awaited for 2020.
FF TC - full frame teleconverter -

APS-C flagship, D FA* 85mm and WA *-prime too.
Also the D FA 70-200mm 4.0.

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