Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
09-18-2010, 07:56 PM   #16
Veteran Member




Join Date: Jan 2010
Location: Vancouver, BC
Posts: 1,421
Original Poster
QuoteOriginally posted by JoepLX3 Quote
Does it also work properly on shorter lenses like for example a 50 mm?
It will work with any lens but not much point in putting it on a 50mm lens. You can probably buy an 85 mm lens cheaper than the combination of 50mm lens plus the 1.7x TC.

Thanks,

09-18-2010, 08:15 PM   #17
Site Supporter
jpzk's Avatar

Join Date: Jan 2009
Location: Québec
Photos: Gallery | Albums
Posts: 7,258
QuoteOriginally posted by sajah Quote
It's a well regarded 1.7x TC, with high quality, but that's not all. It also allows you to use auto-focus on manual focus lenses. This ability is unique to this TC and one Nikon's TC. Plus, until recently, it was discontinued. But now it seems that it's back on production, at least in Japan.

I have one, paid for about USD250 (used) and I have no regret. I use it with my Tamron SP 80-200 2.8 and so far I'm satisfied with the result. With the TC the Tamron max aperture becomes F 4.5, which is still fast enough for me. With good light I usually use F8 anyway.

Check the reviews on
Pentax Lens Review and Specification Database - 1.7x AF Adapter

EDIT: I missed the part where you mentioned about its AF abilities. I thought you didn't know about that. Still, IMO the high price is caused by the rarity, high quality and well the AF ability.
What focal length do you input when using the TC with the Tamron 80-200 lens? Does the K20D prompt you to do that?
I use this 1.7X TC with my DA*300/4 and have to enter 500mm (should be 510mm) but I am not sure how you would calculate the input for a focal "range". Or, does the Tamron lens, because of its already fast F2.8, doesn't need input for focal length?

Just curious.

JP
09-18-2010, 09:43 PM   #18
Veteran Member




Join Date: Jan 2010
Location: Vancouver, BC
Posts: 1,421
Original Poster
QuoteOriginally posted by jpzk Quote
What focal length do you input when using the TC with the Tamron 80-200 lens? Does the K20D prompt you to do that?
I use this 1.7X TC with my DA*300/4 and have to enter 500mm (should be 510mm) but I am not sure how you would calculate the input for a focal "range". Or, does the Tamron lens, because of its already fast F2.8, doesn't need input for focal length?

Just curious.

JP
I don't have the 80-200 f2.8 (not for the lack of trying to get one) but I have the 70-210 f3.5 19AH, and I input the highest focal length 350mm when the camera is turned on. I figure the SR set at the longest focal length would best compensate for the physical length and the weight of the 19AH.
09-19-2010, 03:25 AM   #19
Veteran Member
borno's Avatar

Join Date: Nov 2006
Location: md-usa
Photos: Gallery | Albums
Posts: 2,580
QuoteOriginally posted by jpzk Quote
What focal length do you input when using the TC with the Tamron 80-200 lens? Does the K20D prompt you to do that?
I use this 1.7X TC with my DA*300/4 and have to enter 500mm (should be 510mm) but I am not sure how you would calculate the input for a focal "range". Or, does the Tamron lens, because of its already fast F2.8, doesn't need input for focal length?

Just curious.

JP
When I used that combo, I would set the sr for 135mm as I found after testing, if the sr is set higher than what the FL actually is it can make things blurry. Of course it is easy to reset if you know you are going to be at 200mm for instance.
Tom

09-19-2010, 03:52 AM   #20
Pentaxian
JohnBee's Avatar

Join Date: Sep 2008
Location: front of computer
Posts: 4,620
I use mine with various older lenses and its been great!
My very favorite combo has to be with the Tamron SP 60-300 which actually outresolves digital zoom in certain cases.

K20D, SMC AF 1.7X TC, Tamron SP 60-300mm(@510mm).

Spot focus was on the grass head so the subject is a bit OOF.
09-19-2010, 05:23 AM   #21
Banned




Join Date: Sep 2006
Location: Millstone,NJ
Posts: 6,491
It works great on my K-7 with 85mm F1.4 Rokinon.


[YT]http://www.youtube.com/watch?v=6aSEFjZNbCE[/YT]
09-19-2010, 10:33 AM   #22
Site Supporter
jpzk's Avatar

Join Date: Jan 2009
Location: Québec
Photos: Gallery | Albums
Posts: 7,258
QuoteOriginally posted by JohnBee Quote
I use mine with various older lenses and its been great!
My very favorite combo has to be with the Tamron SP 60-300 which actually outresolves digital zoom in certain cases.

K20D, SMC AF 1.7X TC, Tamron SP 60-300mm(@510mm).

Spot focus was on the grass head so the subject is a bit OOF.
So John, care to tell me what focal length you input for this lens?

JP
09-19-2010, 10:37 AM   #23
Site Supporter
jpzk's Avatar

Join Date: Jan 2009
Location: Québec
Photos: Gallery | Albums
Posts: 7,258
QuoteOriginally posted by borno Quote
When I used that combo, I would set the sr for 135mm as I found after testing, if the sr is set higher than what the FL actually is it can make things blurry. Of course it is easy to reset if you know you are going to be at 200mm for instance.
Tom
So what you are saying is that you input the focal length at the low end of your zoom lens? I am not sure I get the logic behind this as some other people will do just the opposite.
Very confusing.

JP

09-19-2010, 10:38 AM   #24
Site Supporter
jpzk's Avatar

Join Date: Jan 2009
Location: Québec
Photos: Gallery | Albums
Posts: 7,258
QuoteOriginally posted by excanonfd Quote
I don't have the 80-200 f2.8 (not for the lack of trying to get one) but I have the 70-210 f3.5 19AH, and I input the highest focal length 350mm when the camera is turned on. I figure the SR set at the longest focal length would best compensate for the physical length and the weight of the 19AH.
Just the opposite of what Borno is doing!? ...

JP
09-19-2010, 03:55 PM   #25
Pentaxian
JohnBee's Avatar

Join Date: Sep 2008
Location: front of computer
Posts: 4,620
QuoteOriginally posted by jpzk Quote
So John, care to tell me what focal length you input for this lens?
That image was taken at 300mm + TC attached.
I did not us SR (no sense) since handholding at 500mm+ isn't very feasible with such a setup.
09-19-2010, 05:38 PM   #26
Veteran Member




Join Date: Aug 2010
Posts: 523
QuoteOriginally posted by excanonfd Quote
It will work with any lens but not much point in putting it on a 50mm lens. You can probably buy an 85 mm lens cheaper than the combination of 50mm lens plus the 1.7x TC.

Thanks,
Yeah, but I already own 28, 50, 135, 200 mm MF primes (pranning to go for new DA 3.5 mm F2.4) and with the 1.7x AF TC I also "get" 4 AF primes, including a 85 mm (icw 50 mm lens):
- Do you know a good AF 85 mm for sale at reasonable price?
- The MF A* 85 mm F1.4 is like twice as expensive as TC...
- If I like the 85 mm focal length I still might buy a 85 mm either way (AF or MF depending on my experiences and financial situation)

How would it work with Pentax A 35-105 mm F3.5? (for 70 Euro - reasonable?)
- Would it out perform the 50-200 mm kit lens on all fronts?

Last edited by JoepLX3; 09-19-2010 at 05:44 PM.
09-19-2010, 05:43 PM   #27
Veteran Member




Join Date: Jun 2009
Photos: Albums
Posts: 1,679
QuoteOriginally posted by imtheguy Quote
My reason for using converters is the greater flexibility with focal lengths by using shorter telephoto lenses and a variety of high quality TCs.

My two lenses are the DA*300/4 and the A*400/2.8. Depending on where I set up and what I am shooting, I may add a 1.4x, 1.7x or 2x converter to give me the appropriate focal length. If I ONLY had a 600mm lens then I am SOL if I need less. A 250-600mm zoom is a possibility but I have never seen one for sale. IQ degradation is not an issue with the primes unless I stack converters; at least according to my possibly low standards and certainly mediocre eyesight.
Hey stop talking about my love life!!

I have had a desire to grab another Sigma 150-500 (Bigmos) for a long time....I sold my Canon mount long ago. Loved it...so there is something close to your 250-600 but exact and one does need a pack mule to lug it around all day ...but I don't get out of the house much these days so no real need really.

BTW, I never knew about the AF in the TC....it's now on my wish list for sure...if I a going to live with all the primes then the AF makes the old glass even more sexy...see what I mean about "lvoe life???"
09-19-2010, 05:48 PM   #28
Veteran Member




Join Date: Aug 2010
Posts: 523
QuoteOriginally posted by JohnBee Quote
I use mine with various older lenses and its been great!
My very favorite combo has to be with the Tamron SP 60-300 which actually outresolves digital zoom in certain cases.

K20D, SMC AF 1.7X TC, Tamron SP 60-300mm(@510mm).

Spot focus was on the grass head so the subject is a bit OOF.
Nice, shot
- What is effective aperture you used on this shot (I like the OoF effect, but guess you were pretty far away to get this)

QuoteOriginally posted by JohnBee Quote
That image was taken at 300mm + TC attached.
I did not us SR (no sense) since handholding at 500mm+ isn't very feasible with such a setup.
So you if you take the small TC, you also "have to" take the tripod?
- Sounds technically reasonable, but not nice for hiking with family...
09-19-2010, 05:49 PM   #29
Veteran Member
borno's Avatar

Join Date: Nov 2006
Location: md-usa
Photos: Gallery | Albums
Posts: 2,580
QuoteOriginally posted by jpzk Quote
So what you are saying is that you input the focal length at the low end of your zoom lens? I am not sure I get the logic behind this as some other people will do just the opposite.
Very confusing.

JP
My thinking is if the SR is set for 135mm(80 on the lens) and you are zoomed to 340mm (200 on the lens) you will still get some benefit at a reduced amplitude. On the other hand if the SR is set for a focal length longer than what the actual setting is, it will overcompensate and cause blur. Some crude testing I did seemed to bear this out so I went with it. Of course I could be wrong.
09-19-2010, 05:53 PM   #30
Site Supporter
pschlute's Avatar

Join Date: Mar 2007
Location: Surrey, UK
Photos: Gallery
Posts: 1,244
QuoteOriginally posted by jpzk Quote
So what you are saying is that you input the focal length at the low end of your zoom lens? I am not sure I get the logic behind this as some other people will do just the opposite.
Very confusing.

JP
Ideally you should input the focal length that you actually are using for each photo. As this is impractical, you should input a length on the LOW end of the range. If you input too long a focal length you will get blur as the camera will over-compensate.

Ignoring the shake reduction system for a moment, think of the affect the same amount of camera shake will have on two different focal lengths. Obviously the longer the f/l , the more camera shake will affect the image. The shake reduction system works my moving the sensor more for a longer f/l to compensate, so if you input a f/l in excess of what you are using you will get S/R system induced blur.
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, af, auction, ebay, k-mount, lenses, pentax, pentax lens, price, slr lens, teleconverter
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
SMC Pentax 15mm F3.5 on swedish action site (and ebay) melander Pentax SLR Lens Discussion 4 08-21-2008 03:35 PM
For Sale - Sold: Teleconverter Pentax SMC 1.7X AF mimichris Sold Items 2 07-14-2008 08:08 AM
found this Teleconverter on ebay Ilikepics Pentax Film SLR Discussion 3 04-17-2008 10:25 PM
For Sale - Sold: FS on eBay: Tamron 2x teleconverter Finn Sold Items 4 09-11-2007 06:21 PM
1.7x AF teleconverter: £165 on Ebay Durutti Pentax SLR Lens Discussion 5 02-12-2007 07:01 AM



All times are GMT -7. The time now is 05:03 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