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Samyang 800mm F8 DX Review RSS Feed

Samyang 800mm F8 DX

Reviews Views Date of last review
3 34,116 Mon April 28, 2014
Recommended By Average Price Average User Rating
100% of reviewers $236.67 6.00
Samyang 800mm F8 DX

Samyang 800mm F8 DX
Samyang 800mm F8 DX


The 800mm manual focus mirror reflex lens has theálongest focal length of the Samyang mirror lenses, and is often marketed as Rokinon/Opteka/Polar/Vivitar/Bower etc. Also since 2014 there seems to be a Chinese knockoff of this lens listed as 900mm without a brand name.

The lens has a fixed aperture of F8 and can be used in manual as well as Av exposure modes. It covers the 24x36mm full-frame format.

The focus action isá~100░ (reverse to Pentax) andámoves the central mirror and front glass. The construction is metal with a rotating front element.

An adapter is required to mount it on a Pentax camera.

Samyang 800mm F8 DX
©, sharable with attribution
Image Format
Full-frame / 35mm film
Lens Mount
T Mount
Aperture Ring
8 elements, 8 groups
Mount Variant

Check camera compatibility
Max. Aperture
Min. Aperture
Min. Focus
350 cm
Max. Magnification
Filter Size
105 mm (Rear: 30.5 mm)
Internal Focus
Field of View (Diag. / Horiz.)

APS-C: 2 ° / 1.6 °
Full frame: 3 ° / 2.5 °
Lens Cap
Weather Sealing
Other Features
Fixed Aperture
Diam x Length
111x145 mm (4.37x5.69 in.)
946 g (33.4 oz.)
Production Years
User reviews
Discontinued. T mount. An adapter to M42 or K-mount is required in order to mount the lens on a Pentax

Sold under various brand names: Samyang, Rokinon, Opteka, Polar, Vivitar, Bower, and possibly other as well

Buy Lens: Buy the Samyang 800mm F8 DX
Price: 189
Mount Type: Pentax KAF3 (in-lens AF only)
Price History:

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Junior Member

Registered: February, 2009
Location: maisons laffitte 78
Posts: 31

1 user found this helpful
Review Date: April 28, 2014 Recommended | Price: $250.00 | Rating: N/A 

Camera Used: Pentax K3   

well I have just ordered it actually ... I have the 500 f8 too , but thought that for 1/2 the price of the Pentax converter , I would save 1 f-stop for almost same focal length (as well ...) - I'll see !
Site Supporter

Registered: February, 2008
Location: Hawkesbury
Posts: 1,896

2 users found this helpful
Review Date: November 8, 2011 Recommended | Price: $240.00 | Rating: 6 

Pros: long reach, reasonably sharp, resists flare
Cons: low contrast, poor focus design, would benefit from a hood
Sharpness: 8    Aberrations: 8    Bokeh: 6    Handling: 4    Value: 8   

This mirror lens has failings typical of all mirror lenses and then some.
While the lens is all housed in metal and has a smooth focus action, the action is too short. If it had about double the throw in the focus ring, It might be just enough. Many of the newer Samyang lenses have a 250░ focus throw and that is certainly required here.
The lens can take reasonably sharp images but you really have to shoot RAW because the contrast is pretty ordinary. The lens really only comes into its own for bridging vast distances, when the air mass between you and your subject is so great that contrast and precision are already reduced anyway.

I'm going to try adding a lens hood and see if that can improve the contrast issue.

This lens has so many refractive elements that the major advantage of mirror lenses (no colour aberations) is lost. I seem to get purple fringes in many high contrast situations.

One good feature of the lens is that it has one of the best bokeh's in the mirror lens world of donuts. Out of focus highlights can be quite inconspicuous and the focus fall out is also relatively subtle.
Veteran Member

Registered: March, 2009
Location: Perris, CA
Posts: 380

1 user found this helpful
Review Date: April 6, 2009 Recommended | Price: $220.00 | Rating: N/A 

Pros: gives you good reach at an affordable price
Cons: slow

I bought this lens off E-Bay with minimal expectations.

The focus is something to get used to as the depth of field envelope is VERY narrow. The focus ring is smooth and has very little play. I found that pushing the shutter release half way and moving the focus ring slowly, I could get the image focused accurately as long as I had the K20D on manual focus and letting the camera tell me when focus was achieved.

Construction is pretty good. Not a whole lot of plastic and the lens is a bit heavy, but not nearly as heavy as the non-mirror 800mm lens. It feels like it is well made.

I haven't had bad luck with this lens. I have read reviews where people have griped about the fixed f-stop, but as long as you use a steady hand, tripod or monopod you should be good to go.
The pictures attached were all taken at 800 ISO, F8.0 and 1/800 second, hand held and the distance to target was about 80'.

The only drawback is the fixed f8.0 aperture. Either you have to manipulate the shutter speed, keeping in mind the "1/focal length" rule or you have to up the ISO. I have had no problems on bright days going with ISO 200-400 and achieving at least 1/800 second. Longer distances on grayer days using slower ISO may require a tripod/monopod as was previously stated.

The lens I bought came with an adapter for Pentax, a 2X converter, cleaning kit etc for about $220. I haven't used the teleconverter too much yet because I was concentrating on getting used to the lens and manual focus prior to attaching the converter and having to deal with the decreased light etc.

Conclusion: Good lens, worth the money. I already have the 18-55 kit lens and a Tamron LD Di 70-300 1:4-5.6, but the 800mm is better for wildlife photography in my opinion. Not as quick, and not AF, but you can get REALLY close.
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