Small review of the Mamiya 50mm f/4.5 ULD (RZ)

[tron_]

First off, I'm not too sure if this is the right place to put this but I thought I would write up a little review of this lens since I had a little bit of a hard time finding information regarding this lens. If the moderators feel like this isn't the best place for this post, please feel free to move it.

When I bought my RZ67 kit, it came with the 110mm f/2.8 lens. It's a great lens and I really enjoy it but recently I found myself wanting a wide angle more and more. So I debated between the 65mm and 50mm and wound up deciding on the 50mm.

I would browse eBay from time to time to see how prices were and last week I found one for sale for $375. I offered the seller $350 and he accepted. From what I have seen online, this is a pretty good deal

As you guys know, 50mm on the RZ comes out to a focal length of ~24mm on a 35mm film camera. The 110mm is an ~50mm equivalent. The following photo illustrates how wide the 50mm really is:



It’s a bit ugly but hey it’s the function that counts right?

110mm


50mm


Anyways, I went to Ann Arbor with a couple friends this past weekend and I decided it was a good time to use the lens. Please keep in mind these are not my best photos, it was more of a trial to see what I could get from this lens.

I shot these on Ilford XP2 Super shot at 800 instead of the rated 400. I also used a Hoya K2 filter with these.

The lens itself was really a joy to shoot with. The floating optics ring took some getting used to, basically after focusing I had to look at the distance scale on the side of the camera, see how far the subject was, and then dial in that distance on the floating optics ring. Other than that I was pretty surprised to see the the lack of any major distortion with this lens. Yes all wide rectilinear lenses will have distortion but this lens does a pretty good job keeping that distortion to a minimum.

Other than that the lens was very sharp and had tons of contrast (I also shot a roll of Ektar 100) and the colors looked great. Overall I have to say this is a really great lens and I'm happy I bought it. I would definitely recommend it to anyone who is looking for a wide angle for their RZ!

[tron_]

Some photos:

[kbrede]

Thanks for posting this. I went with the 65mm but at some point will probably take a look at the 50mm. What's the "floating optic ring" for?
thanks,

[Ian C]

What's the "floating optic ring" for?

Retrofocus wide-angle lenses of the shortest focal lengths tend to produce a curved field of focus about the subject at extreme close focus. It’s shaped like a portion of a sphere where we expect a lens to produce a flat plane of focus. Some of the better lenses of this type use a single element or two-piece compound element between the front and rear optical units that moves independently of the rest of the lens. The independently moving unit is known as a field flattener. By moving it to the proper position inside the lens assembly, the curved field of focus is flattened as we’d expect of a good lens. The independently-moving field flattener is sometimes described as a “floating element”.

These are moved as necessary by a cam assembly as you turn the focusing ring on helicoid-focusing lenses like 35mm SLR lenses. But the RZ67 is a bellows-focusing camera. In this case we have to turn a “float ring” to manually adjust the position of the field flattener after first focusing the lens. Some close-focusing macro lenses also have an independently-moving field flattener unit. Some examples are the 105mm Micro Nikkor and the Mamiya 140mm macro lens for the RZ67.

[tron_]

Thanks for posting this. I went with the 65mm but at some point will probably take a look at the 50mm. What's the "floating optic ring" for?
thanks,

From what I understand, the floating optic ring controls a piece of focusing glass that is rotated in order to combat astigmatism and promote corner sharpness. I've read that the corner sharpness thing is more noticable at smaller distances though and that most people just set it to infinity and step down. I don't know the optical theory as to what it does, maybe someone smarter than me can tell us more about iit

[tron_]

Retrofocus wide-angle lenses of the shortest focal lengths tend to produce a curved field of focus about the subject at extreme close focus. It’s shaped like a portion of a sphere where we expect a lens to produce a flat plane of focus. Some of the better lenses of this type use a single element or two-piece compound element between the front and rear optical units that moves independently of the rest of the lens. The independently moving unit is known as a field flattener. By moving it to the proper position inside the lens assembly, the curved field of focus is flattened as we’d expect of a good lens. The independently-moving field flattener is sometimes described as a “floating element”.

These are moved as necessary by a cam assembly as you turn the focusing ring on helicoid-focusing lenses like 35mm SLR lenses. But the RZ67 is a bellows-focusing camera. In this case we have to turn a “float ring” to manually adjust the position of the field flattener after first focusing the lens. Some close-focusing macro lenses also have an independently-moving field flattener unit. Some examples are the 105mm Micro Nikkor and the Mamiya 140mm macro lens for the RZ67.

^See above for said smarter guy than me

[Ian C]

I’m no smarter than anyone else. I read the explanations of field flatteners some years ago. These were accompanied by good diagrams to aid our understanding of the mechanism. The flattening unit moves forward and back lengthwise inside the lens barrel. Similar independently-moving units are commonly employed in the design of zoom lenses to change focal length and to keep the field acceptably flat.

[Jeff Kubach]

Good photos. I have a RB67 and a 50, great lens.

Jeff