Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-12-2009, 07:50 AM   #1
Veteran Member
arpaagent's Avatar

Join Date: Sep 2008
Location: Raleigh, NC
Photos: Gallery
Posts: 777
1.7x AF Adapter + RMC Tokina 300mm F5.6

Hey guys,

Recently acquired the lovely Pentax 1.7x AF adapter in a larger auction in great condition. That thing is great, it seems to focus faster that regular AF lenses, maybe because the moving element is so small and light. Anyways, I thought I would share something while testing with it. While Pentax says you should use it with no less than a f/2.8 max aperture for AF to work, most people say they have had some success with an f/4 max aperture lens.

Well, I was trying it out on an RMC Tokina 300mm F5.6 lens this weekend and it was working pretty well. It was a partly cloudy, overcast day, so there was decent light, but it wasn't bright and sunny. As long as I wasn't focusing at a very dark object with zero contrast, it would lock on pretty quickly. I must say I did not expect it to work at all after reading many other comments from people. Here are a few shots with the 300mm lens with and without the TC. Overall, the IQ of the 300mm is pretty good (it's not in the database, but I'll add it soon), even with the 1.7x adapter attached.

All shots were taking with the lens stopped down one stop, at f/8. That would put the ones with the AF adapter at 510mm f/13.6. Very little PP on these. Only exposure adjustment, didn't touch contrast or color from the LR defaults. Looks like I needed to brighten up the first shot now to match the shot with the TC, I realize. Oh well, can't do that at work right now.

Just thought I'd share my experience. Thanks! - Jim

w/o adapter:





w/ adapter:





01-12-2009, 08:46 AM   #2
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,399
you have had better luck than I have with my old vivitar 400mm F5.6 where it is a matter of real luck for the AF to lock (at least it was on my PZ-1)

To be honest, I have not tried since, the adaptor may as well be crazy glued to my 300mm F4, where I use it A LOT

when I first bought this adaptor, it was to use with my PZ-1 and my Vivitrar Series 1 70-210 F3.5. Pentax canada was kind enough to let me try it out at their service center in Mississauga, before I had a camera store order it in.

Since then, I have used it on my 100mm F4 macro, and when I bought the 300 F4 the camera shop owner let me try it out so I knew it would work.

Since the PZ-1 and film, I have used the adaptor on my DSLRs, but have not had the desire to put it on the Vivitar 400 F5.6, that lens basically sits with very little use. The main complaint about the vivitar is that at 22 feet, its minimum focus is not close enough
01-12-2009, 09:01 AM   #3
Veteran Member
arpaagent's Avatar

Join Date: Sep 2008
Location: Raleigh, NC
Photos: Gallery
Posts: 777
Original Poster
QuoteOriginally posted by Lowell Goudge Quote
you have had better luck than I have with my old vivitar 400mm F5.6 where it is a matter of real luck for the AF to lock (at least it was on my PZ-1)

To be honest, I have not tried since, the adaptor may as well be crazy glued to my 300mm F4, where I use it A LOT

when I first bought this adaptor, it was to use with my PZ-1 and my Vivitrar Series 1 70-210 F3.5. Pentax canada was kind enough to let me try it out at their service center in Mississauga, before I had a camera store order it in.

Since then, I have used it on my 100mm F4 macro, and when I bought the 300 F4 the camera shop owner let me try it out so I knew it would work.

Since the PZ-1 and film, I have used the adaptor on my DSLRs, but have not had the desire to put it on the Vivitar 400 F5.6, that lens basically sits with very little use. The main complaint about the vivitar is that at 22 feet, its minimum focus is not close enough
I've been watching for a Pentax 300/4 but I haven't been able to get one yet, I'm sure it's a real screamer with the AF adapter. As far as you AF adapter not working on your PZ-1 with the 400/5.6, Pentax has probably improved the AF systems since then so the AF adapter may be able to cope with less light than they had previously designed it for. It may work with DSLRs, but seems like you are content with the 300mm, which hopefully doesn't leave much to be desired.

I've also tried it out a few times with my Pentax 135/2.5, and that is a very nice combination. It's not ultra-fast as a 230mm f/4.3 or so, but it's really sharp. So far I am very impressed with the AF adapter, and I can understand why people regard it so highly.
01-12-2009, 09:16 AM   #4
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,399
QuoteOriginally posted by arpaagent Quote
I've been watching for a Pentax 300/4 but I haven't been able to get one yet, I'm sure it's a real screamer with the AF adapter. As far as you AF adapter not working on your PZ-1 with the 400/5.6, Pentax has probably improved the AF systems since then so the AF adapter may be able to cope with less light than they had previously designed it for. It may work with DSLRs, but seems like you are content with the 300mm, which hopefully doesn't leave much to be desired.

I've also tried it out a few times with my Pentax 135/2.5, and that is a very nice combination. It's not ultra-fast as a 230mm f/4.3 or so, but it's really sharp. So far I am very impressed with the AF adapter, and I can understand why people regard it so highly.
there is a pretty beat up one in the market place right now for $150

Funny, though, regarding the 135 F2.5, that is the one lens I have never used it with in my collection. generally this lens is a light weight add on to my minimum travel kit of the Sigma 10-20, and tamron 28-75 F2.8. The 135 is a nice length for a little reach and is smaller than the tarmon 28-75, so it is not a big issue to carry it around. I guess I could always take my series 1 70-210 F3.5 or my sigma APO 70-200F2.5, but when I don't see a need for wild life, I also don't see theneed to add 2-3 extra kilos to my load

01-12-2009, 09:28 AM   #5
Veteran Member
Miserere's Avatar

Join Date: Sep 2007
Location: Boston
Photos: Gallery
Posts: 1,994
I've succesfully used the 1.7x TC with a Sigma CAT 400mm f/5.6 and a Tokina 400mm f/5.6. You do need good light, but it works
01-12-2009, 09:32 AM   #6
Veteran Member
arpaagent's Avatar

Join Date: Sep 2008
Location: Raleigh, NC
Photos: Gallery
Posts: 777
Original Poster
QuoteOriginally posted by Lowell Goudge Quote
there is a pretty beat up one in the market place right now for $150
I saw a sigma 300/4 APO in the marketplace for $150, but I didn't see a Pentax 300/4. I was really wanting a Pentax version, for purist sake .

Also, what has been your experience with the 300/4? Are you able to hand-hold it decently, or do you use some sort of support? Even with the AF adapter on it? I know that the K-mount versions don't have a tripod support...until you get to the F* and FA* versions. I was thinking about the SMC Takumar 300/4 because they have tripod mounts.
01-12-2009, 09:38 AM   #7
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,399
QuoteOriginally posted by arpaagent Quote
I saw a sigma 300/4 APO in the marketplace for $150, but I didn't see a Pentax 300/4. I was really wanting a Pentax version, for purist sake .

Also, what has been your experience with the 300/4? Are you able to hand-hold it decently, or do you use some sort of support? Even with the AF adapter on it? I know that the K-mount versions don't have a tripod support...until you get to the F* and FA* versions. I was thinking about the SMC Takumar 300/4 because they have tripod mounts.
look here

https://www.pentaxforums.com/forums/photographers-marketplace/46521-smc-k300mm-f4.html

As to the other questions

best image (note hand held at 1/150 with flash

https://www.pentaxforums.com/forums/attachments/general-pentax-photography/52...-_igp7346a.jpg

tripod mount, I made my own

https://www.pentaxforums.com/forums/attachments/pentax-slr-lens-discussion/47...-100_2666a.jpg

Hand hold, is OK providing shutter speed is up there, remember without shake reduction you need 1/750

I prefer a flash for wild life

For additional images by others there is a long running thread on this lens
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
1.7x, 300mm, adapter, af, contrast, k-mount, lens, pentax lens, shots, slr lens, tc
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tokina RMC 35-105 j2photos Pentax SLR Lens Discussion 7 08-24-2010 06:44 AM
RMC Tokina 80-200mm f/3.5-4.5 Macro - anyone have one? msatlas Pentax SLR Lens Discussion 0 12-24-2009 02:02 PM
For Sale - Sold: RMC Tokina 300mm/5.6 arpaagent Sold Items 1 04-13-2009 10:01 PM
Tokina 17mm f3.5 RMC -spam- Pentax SLR Lens Discussion 4 10-23-2007 09:45 AM
For Sale - Sold: Tokina RMC 35mm F/2.8 XKimZe Sold Items 0 03-27-2007 04:19 AM



All times are GMT -7. The time now is 06:04 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top