Digital Journey 2: Manual Lenses

Part of the benefit of the digital medium format camera is the ability to use legacy lenses such as the Mamiya 645 lenses I have collected over the years. I bought a Kipon shift adapter to M645 lenses for this purpose. 

In order to use the manual lenses with IBIS (In-Body Image Stabilization) one must enter the focal length in the menu system. I place this entry in the 'My Memu' section as well so I don't have to go hunting for it. 

The Kipon adapter works well enough hover I will say it seems to be slightly loose when used with my 2x teleconverter. The teleconverter is not a Mamiya branded one so it may be a combination of the two having slightly sloppy tolerances. The looseness is not excessive, but it is noticeable. The other issue is it allows the lens to focus past infinity. This is probably a precaution on tolerances as people are more likely to complain if they could never focus at infinity. However, it is a pain as you cannot rack the lens to infinity when you know that will work as the result will be slightly out of focus. Every shot must be focused. 

Focusing

Getting the focus sharp is more difficult than the Fuji kit lens even when it is focused manually. The focus peaking and zoom focus aids are much clearer. Since the focus aid is contrast based a higher contrast image is an advantage. Sometime the peaking (which shows high contrast areas) does not appear at all or sparingly with the Mamiya lenses. I have also been testing longer lenses than the kit lens which tops out at 70mm. I have tried my 150mm f3.5 Mamiya and with the 2x teleconverter it becomes 300mm f7. I also have a 55-110mm f4.5 zoom lens that becomes 110-220mm f9 lens with teleconverter.

This means the zoomed image shakes more at times when handheld. Setting the lens type in the camera to utilize the IBIS really helps. I have tried it with the wrong focal length selected and you fight the image stabilization and it makes focus more difficult. 

I have also discovered that even if the focus peaking is showing areas of the desired subject in focus in the normal (un-zoomed) viewscreen chances are the subject will be slightly out of focus. As a consequence I always use the zoom feature to fine tune the focus to get the best results.

Having used the Mamiya lenses quite a bit I have discovered they seem to be lower contrast than the kit lens. This seems to be the root cause of the focus peaking not always being present. The lack of contrast is not always apparent and may be aperture related or related to the scene or how it is lit. This lack of contrast does not impact on the final image as it can be recovered easily in post. (I find it mystifying though as there seems to be no mention of this in the many reviews and videos I have read and watched on adapting lenses.  Below are some examples. 

Unedited image from 150mm f3.5 with 2x teleconverter (300mm)

The above image is the JPEG directly from the camera. Below is the edited version. 

Edited version of above image.

 You can see the image cleans up nicely with some levels and contrast adjustments. 

As for focus on this long 300mm lens setup, I start with a black and white image taken with the kit zoom lens of a ridge at 69mm (35-70mm zoom).

Unedited JPEG with custom black and white film simulation. 
Note trees in center of image. (69mm focal length)

Same trees taken with 300mm lens setup. (unedited)

The trees are very sharp so a very good image can be had.     

Crop of actual pixels (unedited)

I find however the experience is variable. Here is an image taken this last week in the Yorkshire Dales in a woodland. 

Unedited Mamiya 80mm f1.9

With levels, contrast, and sharpening

The above image was taken with the Mamiya 80mm f1.9. This lens is the smallest aperture 80mm from Mamiya. At distance it has a nice soft bokeh.  Upclose it has this strange linear fractured texture. 

Crop to show bokeh

This morning I broke out the only Mamiya zoom lens I have. It is a 55-110mm f4.5 lens. It is pretty big and heavy. It works with the 2x teleconverter I have which would mean I can take it to 110-220mm at f9. I used a fixed ISO of 400 for the early morning light and had little trouble with making exposures between f16 and even f32 thanks to the image stabilization. A few examples on this lens. 

All very pleasing. The dynamic range as indicated by the histogram was quite large in these scenes and the camera handled it well. Having the histogram is almost like cheating. I do have to be careful to notice how much is beyond the highlight and shadow limits. I consistently aim for underexposed if the full range of the histogram is needed. Overfilled pixel bins cannot be recovered whereas the shadows may be. The small histogram in the viewfinder also means that a few highlight (or shadow) areas may not be noticed. 

Aperture Priority

I have recently learned to shoot in aperture priority mode (A on the PASM dial). I started out in manual setting (M) but discovered that the interaction with the viewfinder makes this difficult. If I open up the aperture on the manual lens, then for a given shutter speed the image may be blown out (or too dark) to the point that I cannot make out what I am looking at. My reaction was to adjust the shutter speed until the image in the viewfinder was restored well enough. Later I would have to restore the aperture and shutter speed to take the photo. 

The same problem holds for shutter priority mode (S) by the way. Except it is way worse as the display and histogram never change so you think you have a good exposure but don't until you chimp and look at the result. (I generally don't chimp!) I guess the camera is busy setting the aperture not knowing this is not happening.

Aperture priority means the camera compensates automatically by changing the shutter speed, thus doing what I was doing automatically. Program (P) mode acts the same way with a manual lens attached. In either case it may be useful to set the thumbwheel to ISO control as opposed to the default of shutter speed. This way you can easily flip to a new ISO based on the shutter speed the camera selects. 

If you want to bias the exposure differently from the way the camera set it; then you have two choices. 1) go back to using manual mode (M), 2) use the exposure compensation function. I have my exposure compensation button set to toggle as I don't want to have to hold it down. I press the exposure compensation button then use the rear thumbwheel to increase or decrease the exposure. 

It actually makes sense to leave it this way if I intend to work with manual lenses as this wheel is normally the aperture adjustment which of course has no effect with manual lenses. Indeed, it would be great if I could set the two thumbwheels to default to ISO and exposure compensation if a manual lens is attached. Then switch back if a Fuji lens is attached. 

With exposure compensation this of course changes the shutter speed; this effect happens in both Program (P) and Aperture priority (A) modes. This is useful if you have set the aperture you want, the camera selects the shutter speed for its 'ideal' exposure. You can then manipulate this with the exposure compensation dial. If you do not like the shutter speed it selects, then change the ISO.  

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