Viewfinder and Aperture - Peculiarities... | Shutter Speed Limitation at Wide Apertures | Individual Settings for the Camera Units | Full Press Snap | EXIF Data: Focus Information

On this page, I collect Ricoh GXR specialties, that is, things that are special for the GXR or that you may not know because they are buried somewhere in the manuals or even missing.

 

Viewfinder and Aperture - Peculiarities...

Note: The following is valid for the electronic viewfinder (EVF) as well as for the LCD screen.

On an SLR or DSLR, the lens is at maximum aperture, even during measuring exposure (some old TTL-SLRs stop down during measurement), for keeping the look through the viewfinder bright. A wide open aperture also supports manual focusing, because the low depth of field allows to set the focus more easily (it does not support estimating the depth of field, though...). However, the Ricoh GXR, and at least the Leica X1, work differently. I observed this peculiarity on the GXR when I realized that the review image had a lower depth of field than the image that I saw in the viewfinder before and during focusing. I observed this behavior for normal as well as for macro shots and for automatic as well as manual focusing. However, I did not bother much about this behavior... In April, I read Sean Reid's review of the GXR A12, and when I read the section where he discusses the usefulness of manual focusing with the A12, it fell from my eyes: According to him, the GXR does not have a live view at maximum aperture. Instead, it stops down according to the respective lighting. The reason for this behavior is unknown, and not all EVIL cameras seem to exhibit it (according to Sean Reid, the Panasonic G1 does not show it with the 20/1.7 lens).

Reid also provides an explanation for why I did not realize this behavior initially: It was simply too dark in December and in the subsequent winter months; therefore, the camera did not stop down. However, in April it was much brighter, the camera stopped down, and I realized this peculiarity, however, without having an explanation for it.

Some Details

To verify the above-mentioned behavior, I switched between different modes (P, A, S, M), changed between automatic and manual focusing, and also changed between normal and macro distance. In addition, I tested quick (QK-AF) and normal autofocus (FR-AF), which are no longer available since firmware update 1.29.

In these tests, I could also confirm Sean Reid's observation that in autofocus mode the camera opens the lens to its maximum aperture during focusing, making the image in the viewfinder brighter for a short moment. (After firmware update 1.17 and before firmware update 1.29: This effect is, however, only visible if you use normal autofocus (FR-AF). In quick autofocus (QK-AF), the screen freezes during focusing, and the brightness of the viewfinder does not change. This behavior is valid for normal distance and for macro shots, although in macro mode the effect is often more pronounced because focusing lasts longer. In addition, the brightness effect and the focusing process may also be observable, although the autofocus is set to QK-AF: Obviously, in such a case the camera switched to normal autofocus (FR-AF) automatically.)

M mode shows a different behavior: Here, viewfinder brightness depends on the setting of the f-stop. Depending on the actual f-stop setting, the image may appear brighter during focusing or not.

Finally, overall brightness also has an effect on the visibility of the f-stop change during focusing: On a gray day, aperture may already be at maximum or close to it so that the brightness effect may be barely visible or not at all.

Effect on Manual Focusing

Why do I report this behavior here? The simple reason is that Sean Reid believes it makes manual focusing more or less impossible (at least between spring and autumn...). Based on my observations, manual focusing can indeed be misguided by a smaller aperture and thus larger field of depth. I made a lot of test photos, in which I found that the focus was off in the final result, although it seemed OK to me when I focused manually. According to Sean Reid and to my tests mentioned above, this issue does not seem to exist with autofocus: In autofocus, the GXR opens to maximum aperture during focusing and stops down again afterwards if needed.

 

Shutter Speed Limitation at Wide Apertures

Note: The following text can also be found in the FAQ.

In a thread in the Ricoh forum at dpreview.com from January 2010, among others, the shutter speed limitation of 1/1000 sec at f2.5 for the A12-50 module was discussed. This limitation was attributed to the use of a leaf shutter in the A12-50 module. Here is a list of apertures/shutter speeds limits for A12-50 (from Pavel Kudrys):

The A12-28 module seems to have the same limitations as the A12-50 module. In addition, the S10 module has a similar set of limitations even though it does not use a leaf shutter.

According to barjohn, "the wider the aperture the greater the travel distance each leaf has to make and that is the limiting factor. As you stop down the leaves don't have to travel as far for a given speed to be achieved." This was confirmed by other posters.

benaparis wrote: "Leaf shutter are not designed to have fast speed shutter, if you look at medium format lenses with leaf shutter and lenses for 4x5" and more you will notice that they are not faster... (Some new Phase One leaf shutter lenses allows 1/1600.) It is a choice made by Ricoh, and I agree on that, it as two benefits and a third one:

  1. It is silent... It would have been a huge drawback for me if if the GXR was not as silent as it is...It makes less noise than my Leica MP (which is limited a 1/1000 whatever the aperture chosen but it is not a leaf shutter), that is to say.
  2. It allows you two make very low speed pictures due to lack of vibrations, I can make sharp pictures at 1/5 but easier at 1/15...Of course it depends on each photographer.
  3. You don't have flash synchro limitation, as flash gives an aperture, the speed is used to manage ambient light, it allows you to make creative pictures with flash in daylight... But I must agree that the GXR is not really designed to work with flash."

The only solution to overcome this issue is to use neutral density (ND) filters in bright light. A typical filter may have a reduction factor of 4 (2 f-stops). Pavel Kudrys pointed to a variable ND filter, the Fader ND filter (www.lightcraftworkshop.com/site/page1000.aspx), which allows to change reduction between 2 and 8 f-stops light reduction.

 

Individual Settings for the Camera Units

I always wondered how different settings for camera units can be realized, which is, of course, desirable, because the units are more or less different cameras and therefore require different settings. Nobody is willing to reset settings after changing a unit.

I always had the suspicion that the "Start Settings Readout" would be involved here, but I never tried that. In mid-February 2010, there was a discussion at dpreview about this topic (originating from a thread about a review at Steve's Digicams, and therefore somewhat hidden...). There Ardexx, in a reply to Andrew, pointed to these settings, but it looks as if he has not been successful in using this feature yet.

Anyway, I did a quick check regarding the "Start Settings Readout" and can confirm that at least a number of settings are stored when the settings readout at startup is set to "camera unit." First, I had the S10 attached, when I did the menu setting for startup readout. Then I changed a number of settings, particularly in the adjust menu, to some arbitrary values. Then I switched to A12-50, which showed a lost of "funny" settings: Language changed from German to English, different items in adjust menu etc. I changed that back again but to settings that were different from the current S10 settings. Then, I switched camera units again. The S10 had kept its new settings. I switched another time, set the A12-50 to the values that I wanted it to have, and then again for the S10 and set also values that I want to use. Seems to "work as expected."

Then, I did another check regarding the MY settings. According to this test, the MY settings are stored individually for both camera units if you set the start up readout to "camera unit." You can also save modes like A, S, or P in those settings. Thus, in this case, too, the system "works as expected."

 

Full Press Snap

Full press snap allows users to press the shutter button in one motion when Multi AF or Spot AF is selected as focus mode and switches the mode to snap focus at a preselected distance (2.5m by default). Full press snap is enabled (ON) by default! This functionality had been requested by Harold Glit and implemented by Ricoh according to his specification (as I was told by him), including enabling the function by default. It is intended as a means not to miss a shot due to slow autofocus. The default distance of 2.5m is useful for street photography and many indoor situations. However, it is less useful for landscape shots.

Here is the description of the full press function taken from the GXR manual (adapted):

Full press snap can be disabled or enabled in the menu "Shooting > Full Press Snap" (default: ON). Snap focus distance can be set in menu "Settings > Snap Focus Distance" (default: 2.5m).

First, full press snap is an "expert function." I assume that some users are not aware of it and might overlook it. If users are not aware of this function, they may, however, be puzzled by the results that they get from time to time: unexpected fuzziness. As there is absolutely no indication in the user interface that full press snap took over, it will be very hard for them to find the real reason for the fuzziness. Probably, they will simply assume that Multi/Spot AF has failed.

See my conclusions and suggestions to Ricoh regarding this function.

 

EXIF Data: Focus Information

Elsewhere on my pages, I describe the issues that I had with my S10 module. As I was often not able to memorize at which distances I took my test shots, I would have been happy to find the selected distance, either set manually or by the autofocus, in the EXIF data. Some companies provide such information, but regrettably, Ricoh did not seem to provide it. In July 2010, I had an e-mail exchange with Pavel Kudrys from Ricohforum.com regarding distance information in the EXIF data. Pavel told me that this information is indeed provided, however in some manufacturer-specific fields that are typically not displayed by EXIF viewers. Pavel wrote:

Thus, I had to download and install Exiftool and use the Terminal application on my Apple Macintosh, which is not at all convenient...

BTW: GraphicConverter on the Mac provides information using Exiftool but does not show the manufacturer-specific fields.

Good luck meant, that Pavel had no idea how to decipher the information provided in the 0x0008 field. I took a lot of test shots with different camera units and different focus modes at different distances and collected the values of the tag8 field in an Excel sheet. The values decreased from 1m to infinity and were between 48 and 50 at infinity. Being a physicist, I have some training with numbers, and the natural thing was to normalize the numbers, that is, to divide all values by he value for 1m. That was already the solution: Simply divide the tag8 value by 67108914, the value for 1m, and you get the distance in meters.

Here is Pavel's explanation from a recent thread at dpreview (with a correction by me...):

I would like to add that Multi AF seems to provide a value of 50 for infinity, whereas manual focus seems to provide a value of 49.

Pavel also deciphered the tag for focus mode (Ricoh Image Info 0x0023):

I was less successful with deciphering with field Ricoh Subdir 0x0009, which seems to be related to Multi AF. This field contains numbers that look like powers of 2 or sums thereof (512, 1536, 2048, 2056, 3072, 3585, and many more). Being trained as a physicist, I thought that the 9 AF fields were assigned to certain powers of two and that the sum would indicate, which AF indicators "fired." That would indeed be useful information. However, when I tested my hypothesis, I could not find a consistent pattern in the data. While in some cases, it seemed to work, in other cases, different AF indicator patterns led to the same number and vice versa. Perhaps, someone else will have the right idea here...

 

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01.01.2012