Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-26-2014, 04:32 AM   #61
Veteran Member
TenZ.NL's Avatar

Join Date: Feb 2012
Location: Below sealevel
Photos: Gallery | Albums
Posts: 1,100
QuoteOriginally posted by VisualDarkness Quote
Speed would not be any worse than the common Canon 400/5.6 and DA300 performs nicelly even on a Q so guess there's enough resolution to take from.
I don`t question the resolving power of the DA* 300
But it was kinda late for me last night, after a good night rest the technical side of brain is awake again.
SDM is in the lens, right? So the TC only provides/passes the power for the in-lens system and therefore speed should be the same as without the TC.

I`m not familiar with the Canon 400L f5.6 but Canon`s AF is still (miles) ahead of Pentax. Is this a particulary slow focussing lens?

QuoteOriginally posted by wed7 Quote
$999.99 for this.
-
Well, for such a price Pentax is really doomed

01-26-2014, 04:42 AM   #62
Junior Member
kenez's Avatar

Join Date: Jun 2011
Location: Budapest
Photos: Gallery
Posts: 38
QuoteOriginally posted by JPT Quote
Someone in another thread has posted a picture of what looks to be the long awaited 1.4x teleconverter. It appears to have screw drive and SDM contacts. It also has the AW designation.


https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/236075-tele...ml#post2661032

It looks like a legitimate PR shot to me.
The HD is not lined up with Pentax and the AW at the end too fails to properly line up with Pentax. I'm suspicious that this is a good fake image...
01-26-2014, 05:12 AM   #63
Site Supporter




Join Date: Apr 2013
Location: In the heart of Europe
Posts: 22
QuoteOriginally posted by Kunzite Quote
He also told you: "Keep it secret. Keep it safe"; didn't he?
No, he didn't (explicitly). Otherwise I wouldn't have posted it. His name is Myrddin, not Gandalf ;-).

Last edited by Pentaxoe; 01-26-2014 at 05:50 AM.
01-26-2014, 06:22 AM   #64
ogl
Pentaxian
ogl's Avatar

Join Date: Dec 2007
Location: Siberia
Photos: Gallery | Albums
Posts: 7,112
QuoteOriginally posted by eurostar Quote
If you put this on a FF with a DA21/3,2 you'll have exactly a 29,4/4,48. I don't see any interest to have a 30mm F/4,5 on a fullframe body. I'd buy a cheaper M28/3,5 and surely would have a better image quality.
TC has sense with longer lenses.

01-26-2014, 06:49 AM   #65
Pentaxian




Join Date: Apr 2007
Location: Romania
Posts: 8,409
But people will use it with wide angles, and complain when things won't be perfect
01-26-2014, 07:22 AM - 1 Like   #66
Pentaxian
Fogel70's Avatar

Join Date: Sep 2009
Location: Stockholm, Sweden
Photos: Albums
Posts: 1,737
QuoteOriginally posted by kenez Quote
The HD is not lined up with Pentax and the AW at the end too fails to properly line up with Pentax. I'm suspicious that this is a good fake image...
IMO it looks like a CAD model with the text pasted on. It might be part of some marketing material to be used before manufacturing has started.
So it could be a official fake image from Ricoh,
01-26-2014, 07:40 AM - 1 Like   #67
Pentaxian
Na Horuk's Avatar

Join Date: Feb 2012
Location: Slovenia, probably
Photos: Gallery | Albums
Posts: 10,318
Regards to an earlier question. TC usually only makes sense with tele lenses, to get a focal length that you otherwise couldn't (because it isn't in production or it costs significantly more than a TC and slightly wider lens or the longer lens is big and unwieldy). To use a TC on a 21mm, in terms of FoV, doesn't make sense. Better to buy another lens. But! I think the question was about the image circle. The question is whether this TC enlarges the image circle (and makes it too big for the sensor to use fully), or if it keeps it the size of APSC (which makes sense, because then you have less useless light bouncing in the camera). And I don't know the answer to this question, not for this specific product.
01-26-2014, 07:45 AM   #68
Veteran Member
eurostar's Avatar

Join Date: Dec 2006
Location: Albareto, Italy
Photos: Gallery
Posts: 813
QuoteOriginally posted by ogl Quote
TC has sense with longer lenses.
Oh, sure it has, but it's not what the other poster asked.

01-26-2014, 07:58 AM   #69
Pentaxian
audiobomber's Avatar

Join Date: May 2008
Location: Sudbury, Ontario
Photos: Albums
Posts: 6,631
QuoteOriginally posted by TenZ.NL Quote
I`m not familiar with the Canon 400L f5.6 but Canon`s AF is still (miles) ahead of Pentax. Is this a particulary slow focussing lens?
I reject that statement until I see a credible AF test between a K-3 and 7D.

The DA*300 is fast enough for anything I've done, including BIF and hockey. I owned a Sigma 150-500 and the DA*300 is faster than the HSM on that lens. I don't see why a TC would slow it down, all it has to do is faithfully conduct the electronic signal between the camera and lens.
01-26-2014, 09:08 AM   #70
Senior Member
Serpiente's Avatar

Join Date: Jul 2008
Posts: 154
Pentax K-3 (or successor) + HD Pentax DA 300 F4 DC AW + HD Pentax DA 1.4x TC AW = A winner for wildlife
01-26-2014, 09:10 AM   #71
Site Supporter




Join Date: Feb 2011
Posts: 4,892
I've never seen a credible af test of anything.

The T/C will slow down the af of any lens just because it's halving the light density. Canon and Pentax would be equally affected in theory; in practice Pentax's huge AF sensors would likely be less affected.
01-26-2014, 09:14 AM   #72
Site Supporter
cali92rs's Avatar

Join Date: May 2011
Location: Long Beach, CA
Posts: 3,195
QuoteOriginally posted by wed7 Quote
$999.99 for this.
-
That would be double the price of Canon's 1.4x TC which Is also WR and works with AF. If its that much Ricoh really has no grasp of the market. I will give them a little more credit.
01-26-2014, 09:46 AM   #73
Veteran Member
TenZ.NL's Avatar

Join Date: Feb 2012
Location: Below sealevel
Photos: Gallery | Albums
Posts: 1,100
QuoteOriginally posted by audiobomber Quote
I reject that statement until I see a credible AF test between a K-3 and 7D.

The DA*300 is fast enough for anything I've done, including BIF and hockey. I owned a Sigma 150-500 and the DA*300 is faster than the HSM on that lens. I don't see why a TC would slow it down, all it has to do is faithfully conduct the electronic signal between the camera and lens.
IMHO a comparison between the K3 and the 7D would be apples vs oranges, not only because they don`t share the same lenses but also because of the ageing 7D. Even when it is a draw, that`s quite impressive for an allmost 5 year old body

Well, it slows down because you`re loosing light. A 1.4 T/C will cost you 1 stop of light, a 1.7 TC costs 1 stop and a 2x TC will cost you 2 stops so a DA*300 with 1.4x TC will behave like a 420mm F5.6. From what I understand is that most AFsensors work upto F5.6 (except a few high-end bodies that will go upto F8) and when going over that limit you will loose AFcapability.

Regarding the 150-500: I still have it and in terms of speed it`s no match for my screwdiven 100-300F4, even with the sigma 1.4x EX DG T/C.

QuoteOriginally posted by ElJamoquio Quote
I've never seen a credible af test of anything.

The T/C will slow down the af of any lens just because it's halving the light density. Canon and Pentax would be equally affected in theory; in practice Pentax's huge AF sensors would likely be less affected.
Credits for those who deserve them, you posted this earlier
01-26-2014, 11:07 AM   #74
Pentaxian
audiobomber's Avatar

Join Date: May 2008
Location: Sudbury, Ontario
Photos: Albums
Posts: 6,631
QuoteOriginally posted by ElJamoquio Quote
I've never seen a credible af test of anything.
I have, FNAC Laboratoires. I haven't seen any tests beyond the K-5, but of the results I have seen, the K-x, K-r and K-5 have similar performance to comparably priced and contemporary Canons and Nikons. The K-5 was equal to the D7000, the 7D and D300 beat all other APS-C bodies in AF-C mode (K-5, D7000, 60D).

Last edited by audiobomber; 01-26-2014 at 11:29 AM.
01-26-2014, 11:27 AM   #75
Pentaxian
audiobomber's Avatar

Join Date: May 2008
Location: Sudbury, Ontario
Photos: Albums
Posts: 6,631
QuoteOriginally posted by TenZ.NL Quote
IMHO a comparison between the K3 and the 7D would be apples vs oranges, not only because they don`t share the same lenses but also because of the ageing 7D. Even when it is a draw, that`s quite impressive for an allmost 5 year old body
The 7D still beats the 70D for continuous auto-focus and burst mode. If the Canons you were referencing as being miles ahead in AF are Full Frames, then I won't argue. For APS-C, I don't believe it.

QuoteOriginally posted by TenZ.NL Quote
Well, it slows down because you`re loosing light. A 1.4 T/C will cost you 1 stop of light, a 1.7 TC costs 1 stop and a 2x TC will cost you 2 stops so a DA*300 with 1.4x TC will behave like a 420mm F5.6. From what I understand is that most AFsensors work upto F5.6 (except a few high-end bodies that will go upto F8) and when going over that limit you will loose AFcapability.
You are talking about Canon. Pentax AF is not limited to f5.6 or f8 and will work beyond that. With a DA*300, you lose a stop, from f4 to f5.6. That may affect whether the camera can find focus in some extreme or marginal condition, but not the speed at which the AF moves. The main complaint with SDM is that it moves the lens elements too slowly, especially with the portrait lenses; DA*55 and DA*50-135mm. I'm pretty certain the DA*300 is as fast as a screw drive or competitors' standard micro-motor lenses. It is slower than expensive ring drive lenses.

Note that when stopping down a DA*300 to f8 with a TC mounted, the effective f-stop is f/11, but the focussing is done with the aperture wide open, at f5.6.
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!
1.4x, cameras, da, film, film cameras, forum, full-frame, hd, lenses, pentax, pentax news, pentax rumors, people, teleconverter
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Vivitar 1.4x Teleconverter for Pentax k30? iittoo Pentax SLR Lens Discussion 14 12-27-2013 12:55 PM
Wanted - Acquired: Sigma APO Teleconverter 1.4x EX DG for Pentax Mount iittoo Sold Items 2 05-11-2013 06:44 PM
For Sale - Sold: Tamron-F 1.4X Pz-AF MC4 Teleconverter for Pentax stormtech Sold Items 2 01-24-2013 10:19 AM
For Sale - Sold: Tamron 1.4x Pz-AF MC4 Teleconverter for Pentax dgaies Sold Items 5 02-24-2012 01:38 PM



All times are GMT -7. The time now is 09:00 PM. | See also: NikonForums.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