X2 Teleconverter for my Mamiya 645 Pro
Origins
I was perusing eBay a week or so ago and noticed some 2x teleconverters for sale for the Mamiya 645. I had started using my Mamiya 645 Pro again after a hiatus about 6 or 7 months ago as the UK went into lockdown. I was visiting local woodlands and it made a lightweight outfit for cycling out to some local sites. I also experimented with the 150mm lens I had which was frankly the least used lens of the ones I had. I always thought of it as a portrait lens which is not really my thing.
What is a teleconverter you might ask. A magic bit of optics that sits between the lens and the camera body and doubles the focal length. Sounds great but what’s the catch? The catch is you also double the minimum aperture. So my 150mm f3.5 lens becomes a 300mm (188mm in 35mm-speak) f7 lens. This makes it a less easy to focus as the image is dimmer by two stops.
Well the 150mm lens is great for intimate landscape. Equivalent to about 100mm in 35mm-speak. So when I saw the teleconverter for £29 I thought why not give it a try? I did a little research. This was a Teleplus aftermarket version. The Mamiya branded one was about £120. I wasn't really convinced to pay the extra for what is probably better Mamiya glass. There were plenty of online forum comments that didn't complain about the Teleplus. (The one I received seemed to have never been used with a flawless leather case. )
The Teleplus works with a few more lenses than the Mamiya if that matters. The Mamiya version works on 150mm and longer. Neither works with zoom lenses. The Teleplus works with my 80mm f1.9 which would give me a a 160mm at f4 which is kind of what I have with my 150mm f3.5 for more weight. (When I say a lens does not work I mean it does not fit. The shorter lenses and zoom lenses extend too far into the camera body so on the teleconverter they interfere mechanically. The Mamiya version is apparently a little worse for this hence won't work with the 80mm lens.)
In theory this gives me some different options. The first is my intention.
- 150mm f3.5 without
- 300mm f7 with
Or if I don't like 300mm I could take the 80mm+Teleconverter and leave the 150mm at home. Though I still carry two lenses so I am not sure what this saves.
- 80mm f1.9 with
- 160mm f3.8 without
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| Mamiya 645 Pro with 150mm lens and Teleplus 2x Teleconverter |
Metering
This is not a problem with my prism finder with built-in through the lens metering. It reads the light through the f7 aperture and the teleconverter transmits the changes on the aperture ring to the camera body with a little arm. I confirmed this works on my first roll of film.
If I use an external meter I would have to remember to double the aperture settings on the lens. F3.5->7, f5.6->f11 etc. This is a 2-stop change.
Results
I bought it to see if my 150 mm f3.5 converting to 300mm f7 would be an useful lens. I just completed my first roll of film and I am pleased.
- The metering worked as expected.
- The depth of field is very tight and unforgiving if the focus is off.
- The focus is more difficult to get right on a cloudy day due to the 2 stop dimmer image in the viewfinder.
Because of the razor thin depth of field you will probably want to stop down a bit more and this will force you to a tripod very quickly. I found I could shoot on a cloudy day handheld at 1/30 at f7 with ISO 800 film (HP5+ pushed to 800). When I shot the same film under a forest canopy on a partly cloudy day I was forced to a tripod as my fastest shutter speed was 1/4 of a second at f7.
Below is a digital contact print of this images. some of the images I played with exposure and aperture hence the duplicates. They are well exposed. Some show focus problems when the aperture is open too far. The full sized images have had some small unsharp mask sharpening performed.
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| Digital Contact Print (unsharpened raw scans) |
RAW 0002-0004 were taken handheld at f7 1/30th second. RAW-0002. The branch on the left is already out of focus despite being only slightly behind the trunk. Even the cluster of leaves on the left is not vey sharp.
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| 300mm f7 1/30th |
RAW 0001 and 0005 were taken in a small pond. Both images work for me. They are very sharp but were taken in a meadow so much more available light not being under the forest canopy.
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| RAW 0001 |
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| RAW 0005 |
RAW 0006 and 0007 are the same except 0007 is stopped down to f22 vs f11. RAW 0007 was noticeably softer before unsharp mask was applied. This is despite a tripod being used, mirror was retracted and I took care in the focus.
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| RAW 0006 f22 2-sec |
Images RAW 0008 and 0012 differ in that 0012 was opened up more and again showed softness.
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| RAW 0008 |
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| RAW 0010 f32 |
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| RAW 0011 f16 |
Finally RAW 0013, 0014, and 0015 are increasingly open apertures as exhibited by the background bokeh. The oak leaves soften in the foreground on the right side of these crops as well. I have zoomed/cropped the three images below to show the differences. I believe these are all one stop differences.
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| RAW 0013, 0014, 0015 bottom to top |
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| RAW 0013 |
Conclusions
The exposures are good so I am very satisfied with the metering. Many of these images could have been taken without the teleconverter. Certainly 0006, 7, 8, 10, 11, and 12 could have been taken with the 150mm lens by moving closer. RAW 0013-0015 benefitted from from the longer lens as I could stand back from some underbrush. RAW 0001-005 were not possible due to distance from the subject because of height or water between me and the subject. I would have not achieved as close a crop in these cases had I used the 150mm lens. I did not get a chance to better exercise what I perceive is the biggest benefit of a longer lens. I would like to be able to look across a greater distance to gain some of the benefits of compression of the foreground. Finally this is definitely not a handheld combination even with ISO 800 film. (This, however, has lead me to explore the idea of shooting Ilford 3200 at ISO 1600 to get another stop of speed.)
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