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Rear Converter-A 1.4x-L

Reviews Views Date of last review
8 38,100 Wed March 4, 2020
Recommended By Average Price Average User Rating
100% of reviewers $202.17 9.50
Rear Converter-A 1.4x-L


The Pentax Rear Converter-A 1.4x-L is a professional-quality teleconverter designed for only a small number of lenses.

Features of this teleconverter:

  • Super Multi Coated (SMC) optics
  • Manual Focus
  • Has electrical contacts to support auto-aperture (Tv or P) exposure modes in addition to M and Av
  • The converter does not transmit focal length and MTF information from lens to camera
  • Designed to provide superior image quality on tele lenses 200mm and above
  • Front element measures ~ 3.5cm in diameter and protrudes ~ 2 cm

Supported Lenses:

  • SMC Pentax-DA* 200mm F2.8
  • SMC Pentax-FA* 200mm F2.8
  • SMC Pentax-A* Macro 200mm F4
  • SMC Pentax-A* 300mm F2.8
  • SMC Pentax-FA* 300mm F2.8
  • SMC Pentax-A* 400mm F2.8
  • SMC Pentax-A 400mm F5.6
  • SMC Pentax 500mm F4.5
  • SMC Pentax-F* 600mm F4
  • SMC Pentax-FA* 600mm F4
  • SMC Pentax-A* 600mm F5.6
  • SMC Pentax 1000mm F8
  • SMC Pentax A* 1200mm F8
  • SMC Pentax 135-600mm F6.7
  • SMC Pentax F* 250-600mm F5.6
  • SMC Pentax FA* 250-600mm F5.6
  • SMC Pentax 400-600mm F8-12

This teleconverter is NOT compatible with the SMC Pentax-DA* 300mm F4 and the SMC Pentax-FA* 300 mm F4.5 lenses due to the protruding front element.

Rear Converter-A 1.4X-L
©, sharable with attribution
Image Format
Full-frame / 35mm film
Lens Mount
Pentax K
Light Loss
1 stop
5 elements, 5 groups
Mount Variant (Rear)
Mount Variant (Front)
Weather Sealing
HB-90 or S70-70
Diam x Length
65.5 x 28.5 mm (2.6 x 1.1 in.)
175 g (6.2 oz.)
Production Years
1984 to 2005
Engraved name: REAR CONVERTER-A 1.4X-L
User reviews
The converter retains all exposure modes supported by the attached lens.
The converter does not relay information about focal length, MTF, or lens name to the camera.
The converter is designed for lenses 200mm and longer, but it is not compatible with the DA* 300 mm F4 and FA* 300mm F4.5 lenses. There could be other exceptions amongst the newer lenses due to its protruding front element.

Initially the converter was supplied with a hard case, later with a soft case.

Automatic ApertureFull-Frame SupportDiscontinued
Price History:

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Sort Reviews by: Date | Author | Rating | Recommendation | Likes (Descending) Showing Reviews 1-8 of 8

Registered: February, 2010
Location: Blunsdon,Wiltshire, UK
Posts: 1,246

1 user found this helpful
Lens Review Date: March 4, 2020 I can recommend this lens: Yes | Price: $183.00 | Rating: 10 

Pros: No noticeable loss of sharpness

I recently bought the converter to use with my A*1200mm F8 ED [IF] lens

Pentax K-5/Pentax A*1200mm F8 ED [IF] + Pentax Rear Converter-A 1.4x-L giving 2520mm in 35mm terms.

Moon by Gary Chalker, on Flickr

Moon by Gary Chalker, on Flickr

Moon by Gary Chalker, on Flickr

Moon by Gary Chalker, on Flickr
Forum Member

Registered: February, 2016
Location: Moab, Utah
Posts: 90
Lens Review Date: July 31, 2018 I can recommend this lens: Yes | Price: $280.00 | Rating: 10 

Pros: Sharpness, clarity
Cons: price

One of the best gems from Pentax. I can see no image degradation and almost seems to improve the image. I have no hesitation to use this teleconverter and it is the best teleconverter I've ever used out of about 10 different ones. I also have the 1.4x-S for other lenses, which is an acceptably excellent teleconverter, but this one outperforms it noticeably on the 500. I use mine with M42 to K adapter on S-M-C Takumar 500mm f4.5 and on S-M-C Takumar 400mm f5.6, but it does not fit onto Pentax SMC 400mm f5.6 because of inner baffle.

Registered: January, 2010
Posts: 410

2 users found this helpful
Lens Review Date: May 6, 2014 I can recommend this lens: Yes | Price: N/A | Rating: 10 

Pros: works perfect with my DA*200/2.8, no loss of sharpness, works also perfekt together with HD DA 1.4x AW
Cons: has no AF,

I use this really outstanding Converter together with my DA*200. The results are outstanding for a Converter. There is no loss of sharpness or contrast. It outperforms the F 1.7x AF Adapter and is also better than the new HD DA 1.4x AW Rear Converter. Espesally in the corners this old Converter outperformsall other Converter I have seen. But the DA*200 is the only modern Lens you can actually buy new, which fits with the A 1.4x-L Converter.

But the best thing nowadays is: The A 1.4x-L works perfectly in Combination with the new HD DA 1.4x AW and the results are outstanding quality. With the DA*200/2.8 you can get a 280/4 or a 400/5.6 lightweigt Travelcombi if you also own the new HD DA 1.4x AW Rear Converter. 400mm with a nearest focussing distance of 120 cm!!!

I can't post Images here but you can see some samples of the convertercombination here (DA*200 + A1.4x-L + HDDA1.4xAW):

Registered: February, 2007
Location: Prevost, Quebec, Canada
Posts: 410
Lens Review Date: January 12, 2012 I can recommend this lens: Yes | Price: $225.00 | Rating: 10 

Pros: Very effective TC, no loss of sharpness
Cons: Only fits my A*600mm

This one of my best purchases, realy works well and does not add much weight. Nice bokeh.

By ramiot at 2011-07-04

By ramiot at 2011-06-08
Loyal Site Supporter

Registered: March, 2009
Location: Virginia Beach
Posts: 2,950

1 user found this helpful
Lens Review Date: July 27, 2010 I can recommend this lens: Yes | Price: $225.00 | Rating: 9 

Pros: No obvious degradation to image quality
Cons: Not usable with most popular lenses, like DA*300/4

This is the only TC I have used that did not degrade the image at all when viewed or printed normally. Therefore it is the only 1.4x I can recommend that is clearly better than just cropping. I use it coupled to an A*400/2.8 and at 560mm I prefer manual focus anyway at that FL .

Its as good as it gets if you only need 1.4x and have a lens it will fit.
Forum Member

Registered: August, 2007
Location: Cambridge, United States
Posts: 57
Lens Review Date: March 22, 2010 I can recommend this lens: Yes | Price: $150.00 | Rating: 9 

Pros: Stunning glass, doesn't really degrade IQ
Cons: Protruding front element, build quality

Some absolutely stunning glass... I pair this with a 400mm f5.6 (which I have reviewed too), and I get images that I am really very pleased with. I can't really tell the difference between the 400mm images and the 400mm + TC images, which, I think, is exactly what you want in a TC.

My only issue with it (aside from the protruding element, which I assume is what makes it so good, so I can forgive it that) is that the rubber on the grip of mine has started to come off, ever so slightly. I assume it was left in the sun before I bought it, which caused expansion. Then again, it's not a new piece of kit.

Some images with the 400 + TC:
Site Supporter

Registered: February, 2008
Location: MT
Posts: 1,286
Lens Review Date: October 17, 2008 I can recommend this lens: Yes | Price: N/A | Rating: 9 

Pros: optimized for telephoto use, sharp.
Cons: mount screws wiggle loose, color shift with 600/4

Astounding sharpness and clarity coupled with A*200/4 Macro. Almost unnoticeable sharpness decline. That is very rare for teleconverters and I'm quite picky. Absolutely blows the 1.7x Autofocus "toy" out of the water.
Quite sharp coupled with F600 and FA600 tele's but causes slight color shift--particularly in the green color range. The color issue is unnoticeable unless comparing side by side images with and without the teleconverter. Primarily noticeable in sunlit images.
I've owned a couple of these and both needed occasional screw tightening around the mount area. If left loose, the mount has enough slop to decrease sharpness.
This is a truly "pro" quality teleconverter with strong build quality and way better than expected image quality. By far the best Pentax choice for the lenses it can work with. Autofocus? What's that, I almost never use autofocus so don't miss it with this manual converter.
Site Webmaster

Registered: September, 2006
Location: Arizona
Posts: 49,615
Lens Review Date: September 15, 2008 I can recommend this lens: Yes | Price: $150.00 | Rating: 9 

Pros: Superior Image Quality, Auto Aperture
Cons: Only usable with certain tele's

This is a superb and relatively compact teleconverter, that when coupled with a tele such as the 300mm FA* or 500mm K, provides excellent image quality. Unfortunately, it can't be used with most tele zooms, so its use is very limited.

Here's a sample photo taken with the K 500mm F4.5 (effectively a 700mm F6.3 with the teleconverter on), followed by a 100% crop, which just about says it all:

I'd recommend this teleconverter to anyone who frequently shoots tele. Since it lacks autofocus, however, it's not as useful for action shots or birding, but the loss of one and a half F stops is definitely a good trade-off considering the sharpness and added reach it offers.
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