As discussed in the first review post, the M module is a departure from the original GXR concept of lens-sensor combination. One aspect of it is that, with the lens component dropped, the M module adopts a focal plane shutter instead of a central shutter for the other two A12 modules. This is because the focal plane shutter allows the use of interchangeable lenses without requiring the extra cost of fitting in a separate shutter in individual lens. But there are some inherited disadvantages to a focal plane shutter. Let’s look briefly at the three most prominent ones.
Three Disadvantages
The first one is the louder shutter noise. To those traditionalists who may have a penchant for everything nostalgic, the M module’s solid, deeper shutter sound could be rather sexy. To me, it sounds as do any usual mechanical film cameras. One may wish for a quieter operation in certain situations as I did in doing shots in indoor settings. Silence operation is especially important for doing stealthy candid shots too. But the M module is a head turner in the first place, not to mention that it requires all the attention-seeking manual focus tweaking. To overcome this shortcoming, the M module features an electronic shutter mode for silent operation in case of need.
The next disadvantage is that unlike a central shutter (which opens fully to allow flash sync at all shutter speeds), the focal plane shutter restricts the flash sync to 1/180s top. Unfortunately, this maximum flash sync speed applies to both the physical and electronic shutters of the M module. The saving grace is that the electronic shutter mode allows a speed of 1/8000s top (double the maximum speed of the physical shutter) which can therefore double as a ND-equivalent substitute in case one needs to use a larger aperture under a bright sky. A side note is that the base ISO of the M module is ISO 200.
(The 35mm lens is equivalent to 50mm with the APS-C sensor. The shots were taken at 1/30s -- two stop away from the safe shutter speed -- along with the same exposure combo. My notes read: the upper left one is not properly focused; the upper right and lower left ones are blurred as I held the camera in a casual position; then for the lower right one, I leaned against something with my elbow pressed against my chest to steady the camera)
Third, beyond the safe shutter speed, the camera can be vulnerable to shutter vibration due to the mirror-slap of larger curtains. I have no laboratory proof to substantiate the suspicion of the module’s vulnerability to mirror-slap vibration, but judging from the results of several hundreds of shots, the images are likely more prone to blurring at two or more steps below the safe shutter speed – not ideal by the standard of digital cameras but similar to the result with film cameras. That said, the above shots were done to prove how worse it went. Under normal circumstances, I always apply the old techniques (lean against a wall, elbow rest against the chest, take continuous shots, etc) to prevent blurry shots. And there are other ways to get a safer shutter speed. So far, the results I got with the M module are predominately steady shots.
Another musing is that since the GXR body is tiny and the safe shutter speed corresponds with the focal length, I would like to see how the GXR M module mounted with a heavier, manual telephoto lens fares in terms of making steady shots.
Two Unique Functions
Let’s move on to two photographic functions unique to the M module. First, there is the Peripheral Illumination Correction which allows correction levels adjustable between -3 and +3. According to the FAQs page on Ricoh’s official website, it is there supposedly for brightening up the corners. But the better way to utilise this function is to leave it at -3 to give the final images a taste of lomo images with dim corners. Personally, I quite like this effect for it bestows the image with a more purified tone and nostalgic mood.
The M module also features a Colour Shading Correction function which allows adjustment of individual corners for pinkish colour shades typical to lenses sitting close to the sensor, such as the Voigtländer lens used for the review.
The Voigtländer lens is prone to a pinkish cast over the brighter area of a scene under the bright sky. This doesn't happen all the time but is more noticeable as the aperture opens up wider. However, when it occurs, the lens sometimes does not bulge and the pinkish cast cannot be removed even under the strongest shading correction level. Take the following shot for example. The correction was tuned up to the maximum for both upper corners (red minus 4) but the corrected image on the right doesn't look quite correct.
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One may try a simple and effective way to work around the issue. It is to stop the aperture down to f11 or narrower while compensating the exposure by tuning up the ISO value or slowing down the shutter speed. For the corrected shot here, the aperture was closed down to f22.
High-ISO Performance
(@ISO 3200; 100% crop below) |  |  |
The M module is fitted with the same 12MP sensor as the A12 50mm and 28mm modules, but has done away with the low-pass filter. So, together with the higher optical quality lens, the M module produces pictures of gobsmackingly good quality at even ISO3200. Take for example the above shot taken at ISO 3200 (with Voigtländer Nokton 35mm F1.2 ASPH II): the image excels in terms of details (see the tiny Chinese characters above the "KM"), noise level (suitably suppressed) and colour accuracy (the metallic colour and the reflected images). Readers should note that noise level will be more noticeable in darker areas of a scene. And I chose this dimly lit street scene just to strain the noise extent a bit.
On this note, we will see some side-by-side shots taken with the M module and the Sony A55 for comparison in the next post. As for now, readers who are interested in seeing the excellent details and colours reproduced with the M module, look no further beyond Crist's Hong Kong shots here and here.
Tomorrow, we will be focusing on the lens.
(Kudos to Laikok for lending GX Garnerings the camera unit and the lens)
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