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Rear Converter-A 645 1.4X Review RSS Feed

Rear Converter-A 645 1.4X

Reviews Views Date of last review
2 16,838 Sun June 28, 2015
Recommended By Average Price Average User Rating
100% of reviewers $200.00 9.00
Rear Converter-A 645 1.4X

Rear Converter-A 645 1.4X
Rear Converter-A 645 1.4X


The Pentax Rear Converter-A 645 1.4X multiplies the focal length by 1.4 at the expense of one stop of light. It supports all exposure modes of the attached lens. The converter can be used with manual focus as well as autofocus lenses. Even with an autofocus lens attached, the resulting lens/rear converter combination will focus manually only.

Refer the notes in the table as regards lens compatibility.

Rear Converter-A 645 1.4x
©, sharable with attribution
Image Format
645 film
Lens Mount
Pentax 645
Light Loss
1 stop
5 elements, 4 groups
Mount Variant (Rear)
645 A
Mount Variant (Front)
645 A
Weather Sealing
Diam x Length
77 x 31 mm
265 g
Production Years
(in production)
Engraved name: REAR CONVERTER-A 645 1.4x FOR 1:4 300 mm
User reviews
Dedicated to the 645 A* 300mm lens. Also suitable for A and FA 120mm, FA 150mm, A and FA 200mm, FA* 300mm, FA 400mm and A* 600mm lenses.
The converter supports all exposure modes of the attached lens.
Autofocus lenses can be focused only manually with this converter.
Automatic ApertureMedium-Format Support
Price History:

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Sort Reviews by: Date | Author | Rating | Recommendation | Likes (Descending) Showing Reviews 1-2 of 2
Site Supporter

Registered: November, 2011
Location: pontiac mi.
Posts: 366
Lens Review Date: June 28, 2015 I can recommend this lens: Yes | Price: N/A | Rating: 9 

Pros: light, easy hookup,
Cons: manual focus only.

so sharp you can see individual hairs on the arm, no loss of IQ that I can see. the fact that Pentax sells it says that it has to be good.
Site Supporter

Registered: November, 2008
Location: Washington DC, USA
Posts: 563
Lens Review Date: November 6, 2010 I can recommend this lens: Yes | Price: $200.00 | Rating: 9 

Pros: Light
Cons: No AF

This is a nice little converter. It works with more than just the A 300mm f/4. I have used this with my Pentax FA 400mm f/5.6 and the FA 120mm f/4 macro.
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