Prime?


Frogfish

Link Posted 06/04/2011 - 18:25
Can't argue with that shot Algi, lovely sparrows you have up there, but that's hardly the typical use for a TC !

Normally people want the extra length to capture birds or wildlife that would otherwise represent a little dot in the shot, being easily mistaken for a speck of dust ! The 55-300 is slow enough without a TC - add even just the x1.4 and you're looking at f8 minimum and it's an absolute dog to achieve focus in anything less than great light. Add in the variable focal length - and that's why TCs are not recommended on the 55-300 (especially since the 55-300 achieves it's best sharpness at between 200 & 260).

As someone else said earlier - TCs are primarily made for primes.
http://frogfish.smugmug.com/ Pentax. Pentax DA*300/4, Cosina 55/1.2, Lens Baby Composer Pro & Edge 80, AFA x1.7, Metz 50 af1.
Nikon. D800. D600. Sigma 500/4.5, Nikon 300/2.8 VRII, Sigma 120-300/2.8, Zeiss Distagon ZF2 21/2.8, Zeiss Distagon ZF2 35/2.0, Sigma 50/1.4, Nikkor 85/1.8, Nikon TC20EIII, Nikon TC14EII, Kenko x1.4, Sigma 2.0
Last Edited by Frogfish on 06/04/2011 - 18:26

Algernon

Link Posted 06/04/2011 - 19:08
Frogfish wrote:
As someone else said earlier - TCs are primarily made for primes.

Strange?.... most of the tests I've seen in magazines were a TC on a zoom lens, usually 70-200mm in the film days. Losses were often only 5% to 10%. If you just blow up the non TC shot by 2x you immediately lose 50% of the resolution, so 10% loss with a TC is much better.

A lot of top Canikon togs use TC's with zooms.
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi

petrochemist

Link Posted 06/04/2011 - 19:18
Brilliant Shots Algi, But that's never a sparrow!
Mike
.
Pentax:K5ii, K7, K100D, DA18-55, DA10-17, DA55-300, DA50-200, F100-300, F50, DA35 AL, 4* M50, 2* M135, Helicoid extension, Tak 300 f4 (& 6 film bodies)
3rd Party: Bigmos (Sigma 150-500mm OS HSM),2* 28mm, 100mm macro, 28-200 zoom, 35-80 zoom, 80-200 zoom, 80-210 zoom, 300mm M42, 600 mirror, 1000-4000 scope, 50mm M42, enlarger lenses, Sony & micro 4/3 cameras with various PK mounts, Zenit E...
Far to many tele-converters, adapters, project parts & extension tubes etc.

.[size=11:].Flickr WPF Panoramio

puma

Link Posted 06/04/2011 - 19:22
Hey were is Stefan??????????
my web site http://www.swilsonphotography.foliopic.com/
PPG link

Gwyn

Link Posted 06/04/2011 - 20:15
puma wrote:
Hey were is Stefan??????????

Having a break again. Maybe his photo course is keeping him busy. No doubt he'll return at some point.

Frogfish

Link Posted 07/04/2011 - 01:48
Algernon wrote:
Frogfish wrote:
As someone else said earlier - TCs are primarily made for primes.

Strange?.... most of the tests I've seen in magazines were a TC on a zoom lens, usually 70-200mm in the film days. Losses were often only 5% to 10%. If you just blow up the non TC shot by 2x you immediately lose 50% of the resolution, so 10% loss with a TC is much better.

A lot of top Canikon togs use TC's with zooms.

Not really strange and absolutely true ... you need to guess and then input via the menu (or switch your camera off and on in between every change of focal length) the FL with a zoom if you want your SR to work accurately and not affect (blur) your shots ! Naturally this isn't an issue with primes, which generally (and that's a helluva generalisation) have better IQ anyway so the slight loss in IQ is less apparent.

Most Pros use TCs with long primes - Pros don't often use long zooms at sporting events (and definitely not with TCs which would make the lenses too slow - in two senses of the word), just look at the plethora of white at any football match !
http://frogfish.smugmug.com/ Pentax. Pentax DA*300/4, Cosina 55/1.2, Lens Baby Composer Pro & Edge 80, AFA x1.7, Metz 50 af1.
Nikon. D800. D600. Sigma 500/4.5, Nikon 300/2.8 VRII, Sigma 120-300/2.8, Zeiss Distagon ZF2 21/2.8, Zeiss Distagon ZF2 35/2.0, Sigma 50/1.4, Nikkor 85/1.8, Nikon TC20EIII, Nikon TC14EII, Kenko x1.4, Sigma 2.0

johnwhit

Link Posted 07/04/2011 - 07:14
Frogfish wrote:


Not really strange and absolutely true ... you need to guess and then input via the menu (or switch your camera off and on in between every change of focal length) the FL with a zoom if you want your SR to work accurately and not affect (blur) your shots !

That won't work with a modern AF lens on a Penta DSLR as the camera obtains the FL automatically. If I fit the DA* 300/4 + 1.4, 1.5, or 1.7x TC to the K20D (420, 450 or 510mm) the camera still sees the lens as 300mm!
So it's time to switch SR off and get the tripod out, unless you use an old manual focus TC with no contacts on the back and then you lose AF

John
PPG link

In LBA hiatus.

K10D

Link Posted 07/04/2011 - 08:15
wuttwutt wrote:
I would really just like to take good pictures at a greater distance. Wildlife is that target.

You probably need to consider a different system. It comes down to using the right tool for the job and at present, Pentax do not offer the right tool as far as glass in concerned.

The down side is cost. Long, fast glass with or without matching TC's means large sums of money.

Best regards.

johnwhit

Link Posted 07/04/2011 - 08:23
K10D wrote:

You probably need to consider a different system. It comes down to using the right tool for the job and at present, Pentax do not offer the right tool as far as glass in concerned.

The down side is cost. Long, fast glass with or without matching TC's means large sums of money.

Best regards.

You mean to say buy a Canikon

Why not try one of these:

http://www.sigma-imaging-uk.com/lenses/telephoto/500mm.htm

In Pentax fit of course, a snip at 4799.99 or even cheaper if you shop around

Or maybe a secondhand Sigma 400/5.6 APO TELE MACRO 350 for a good one if money is tight.

John
PPG link

In LBA hiatus.

Algernon

Link Posted 07/04/2011 - 10:23
Algernon wrote:
Frogfish wrote:
As someone else said earlier - TCs are primarily made for primes.

Strange?.... most of the tests I've seen in magazines were a TC on a zoom lens, usually 70-200mm in the film days. Losses were often only 5% to 10%. If you just blow up the non TC shot by 2x you immediately lose 50% of the resolution, so 10% loss with a TC is much better.

A lot of top Canikon togs use TC's with zooms.

Sigma list their TC's for use with Zooms as well as primes.
A 70-200mm f/2.8 +TC is a very popular combination
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Last Edited by Algernon on 07/04/2011 - 10:24

thoughton

Link Posted 07/04/2011 - 12:36
Despite owning that Sigma 70-200 plus the Sigma TCs, I would still agree that on the whole TCs should only be used with primes. Yes there are some very high quality (dare I say 'prime-like' ) zooms which will give good results with a TC, but they are few and far between.

I've seen good results from the Sigma 70-200s awith TCs, and the Pentax 50-135 with 1.7x TC. Can't think of any other combinations at the moment.
Tim
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27, Macbook Pro 17, iPad, iPhone 3G
Flickr Fluidr PPG Street Portfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!
Last Edited by thoughton on 07/04/2011 - 12:37

johnwhit

Link Posted 07/04/2011 - 13:18
thoughton wrote:
I've seen good results from the Sigma 70-200s awith TCs, and the Pentax 50-135 with 1.7x TC. Can't think of any other combinations at the moment.

Yes the Sigma 70-200/2.8 works reasonably well with the dedicated 1.4x and 2x TC's I've used them myself and apparently the Sigma 100-300/4 is pretty good as well with the 1.4x, see:

http://www.photozone.de/nikon--nikkor-aps-c-lens-tests/369-sigma-af-100-300mm-f4...

Unless Sigma have redisigned the TC's they don't work with SDM or even Sigma's own HSM
It's about time they got that sorted.

John
PPG link

In LBA hiatus.

Algernon

Link Posted 07/04/2011 - 13:24
This is a good test with Canon Zooms and 1.4X and 2X TC's.

The Conclusion reached:

"The most significant conclusion that I can draw from these tests is that the 70-200mm f2.8 mkII can be freely used with converters and still totally hold its own against the bare 100-400 lens.I now feel that I don't need to own both a 70-200 and a 100-400 as the 70-200 mkII can do it all."
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi

johnriley

Link Posted 07/04/2011 - 13:30
But what relevance does a test of Canon lenses and Tcs have to Pentax Users?
Best regards, John

thoughton

Link Posted 07/04/2011 - 13:31
Well ... I wish the Sigma 70-200 and TCs were as good as those Canons, but they're not: link. None of mine were sharpened but especially the 2x looks much worse than the Canon 2x.
Tim
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27, Macbook Pro 17, iPad, iPhone 3G
Flickr Fluidr PPG Street Portfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!
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