How is Manual Focusing Supported on the GXR? - Overview | GXR Manual Focus Methods | Support for "Pure" Manual Focusing | Conclusions | Appendix: General Manual Focusing Methods

On this page, I describe how manual focusing works with the GXR camera units.

Note: For the M-mount unit, see the Manual Focusing with the GXR M-Mount Unit.

 

How is Manual Focusing Supported on the GXR? - Overview

Depending on the needs of the photographer, the GXR offers several methods of focusing manually:

"Pure" manual focusing is furthermore supported in several ways:

Enlargement was considerably improved and focus assist introduced with firmware update 1.40, which accompanied the release of the M-mount expansion unit.

 

GXR Manual Focus Methods

The focus methods can be selected in the "Shooting" menu. Using item "Focus" you can select from the following modes: Multi AF, Spot AF, MF (manual focus), Snap (fix focus), and infinity. Furthermore, you can activate/deactivate full press snap (item "Full Press Snap", default: "on") and set the snap focus distance (item "Snap Focus Distance") there.

You can assign the "Focus" selection menu to one of the four "Adjust lever settings", which I always do.

Furthermore, you can assign the "MF/AF" selection to one of the two function buttons ("Fn1" or "Fn2"). I use this for the two A12 camera units (A12-50 and A12-28), particularly for switching to manual focus in macro mode for the A12-50.

Snap Focus

Snap focus allows you to preset the focus distance according to your needs. For example, street photographer may want to set the distance at 2.5m, which is also the default. Infinity is a "special" fixed distance, which can be directly set from the "Focus" menu.

Values: 1m, 1.5m, 2m, 2.5m, 3m, 3.5m, 5m, infinity

For snap focus, including infinity, a distance scale appears in the viewfinder with a green depth-of-field indication (see below).

I use the infinity setting typically for sky photos, when Autofocus cannot find a target. Sometimes, I use it also for landscape and architectural shots, particularly with wide angle lenses. As I am not a "streetshooter" I neither use snap focus nor full press snap.

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 to overrule AF. It switches the focus mode to snap focus at a pre-selected distance (2.5m by default). This functionality 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.

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

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

As snap focus is "on" by default, it can puzzle users who do not know of the existence of this feature. Therefore, I decided to disable it. I discuss this issue on pages Specialties and Pitfalls of Full Press Snap.

Manual Focus (MF)

Manual focus (MF) allows you to set the focus at your own will. Depending on the camera unit, you change the focus manually by:

Apart from the A12-28 camera unit that does not have a macro function, you can switch from normal to macro mode and vice versa by simply turning the focus ring or the up-down dial. Personally, I find having to press the "Macro" button for focusing not very comfortable when using the EVF with the left eye.

Like for snap focus, in manual mode a distance scale appears in the viewfinder with a green depth-of-field indication (see below).

Manual focusing can be performed using:

For example, you set the distance in advance and correct it using the viewfinder/LCD screen. See also the "Appendix Manual Focusing Methods" below.

Manual Override of Autofocus

With the A12 camera units, you can override autofocus and use the focus ring to fine-tune the focus. You can do so as long as you press the shutter button down halfway after autofocus has settled. Pressing the shutter button once again cancels the manual fine-tuning. I have to admit that I use this function only in rare cases.

You have to enable this function in the "Setup" menu by setting item "Focus Ring Settings" to "AF+MF" (default).

Focus Lock

Locking the focus at a certain distance for one or more shots is useful in a number of occasions, such as sport photos where AF is too slow, series of photos, etc. (one might debate whether this is a manual focus method, but it fits in here...). The GXR provides the following options for locking focus:

The "AF/MF" function has the additional advantage that it sets the manual focus to the distance that AF has set. Thus, for pre-focusing you can first use the AF to set the appropriate distance and then switch to manual focus. Of course, this works only in cases where AF finds focus (for example, it may not work for sky or macro photos).

While the technique of pressing the shutter-release button down halfway is easy to use (and I use it quite often), the coupling of exposure and focus lock can lead to problems. For example, when I take a picture of a landscape, and the image looks too dark, I point the camera lower to brighten the image up - but now the focus may be too close. The other way round, when I point the camera to the sky to darken the image, focus may not find a target.

 

Support for "Pure" Manual Focusing

Depth-of-Field Display

For all manual focus modes in Ricoh lenses, a distance scale with depth-of-field indication is displayed in the viewfinder/LCD display. This allows you to apply the so-called "zone focusing" method or to set the "hyperfocal distance" (everything is sharp from a certain distance up to infinity). Although this is best used with true manual focus (MF), you can, at least, observe what is going on and, for example, change the aperture to extend the depth-of-field to a kind of hyperfocal distance...

         

Photo: Distance scale with a green depth-of-field indication (A12-50 left and center, P10 right); the center photo show a kind of "hyperfocal" distance setting

Magnification

A section of the picture can be magnified 2x, 4x, or 8x (since firmware update 1.29) ("Enlarged View mode"). The enlarged section is either shown in a section of the display (lower quality) or full screen (better quality) (since firmware update 1.40). The enlarged section can be moved in either mode.

Note: The Ricoh GXR manual as well as the menus sometime use the term "magnification" and sometime speaks of "enlarge"...

Basic Procedure

Thus, by repeatedly pressing the "Menu" button for a about a second, you can cycle through the magnification modes.

         

Photos: No magnification (left), "Enlarge Part" (center), and "Enlarge All" (right); in the latter case, a small display indicates where the enlargement is located in the image

Details

If you want to avoid cycling through the modes you can can set either "Enlarge All" or "Enlarge Part" to one of the function buttons Fn1 or Fn2. I use this setting for the M-mount expansion unit, not for the regular camera units.

Magnification ratio can be set in the "Shooting" menu (item "Magnification" ratio). You can change the magnification ratio dynamically by pressing the selftimer button for more than a second. Then you can select between a magnification of 2x, 4x, or 8x.

You can move the enlarged section of the screen ("Mode Target") by pressing the "Adjust lever" button, then selecting the AF/AE setting in the fifth tab of the "Key Customs Settings", and using the direction buttons. Personally, I find this function only useful if the camera resides on a tripod. In other words, I never use it...

When you half-press the shutter-release button in "Enlarge All" mode (fullscreen), magnification is turned off, and you see the image in normal magnification so that you can frame the photo. This is not the case for the "Enlarge Part" mode (but the manual does not distinguish between both modes). Personally, I prefer the behavior of the "Enlarge All" mode.

Last, but not least, in the "Setup" menu you can set that enlargement is turned off after shutter-release (item "Zoom Display Release") so that you have to turn it on when you need it again:

"Secret" Information

Now comes information that you cannot find in the manual. First, the quality of the 4x and 8x enlargement has clearly improved since firmware update 1.40. Secondly, the image quality of fullscreen mode ("Enlarge All") is considerably better than when only a section of the screen displays the enlarged section ("Enlarge Part"). For manual focusing it is therefore evident that only an enlarged fullscreen view is useful - I often use it even without focus assist.

My Preferred Settings

Currently, I initiate magnification mode by pressing the "Menu" button. Usually, I set the magnification ratio to 4x or 8x. I prefer "fullscreen" magnification, but do not want to loose a function button for setting it (I use one for switching AF/MF and the second one for focus assist), so I have to cycle through the modes...

Focus Assist

The GXR offers two methods for supporting manual focusing:

There is no cycling through the focus assist modes as there is for the screen magnification mode and macro modes. You have to select the mode in the "Setup" menu, item "Focus assist selection" (Mode 1 or 2). There is also no button for selecting a focus assist mode (after pressing it for a second). Actually, there is no button available any more, but maybe Ricoh will find a solution... As you can see, Ricoh is inconsistent here in comparison with the magnification and macro modes...

Here are sample photos without and with focus assist:

         

Photos: No focus assist (left, focus assist mode 1 (center) and mode 2 (right)

Most users prefer focus assist mode 2, whereas I prefer mode 1 or no focus assist at all, that is, only full screen magnification. Focus assist can, of course, be combined with screen magnification.

 

Conclusions

For "normal" photos, I use manual focus only on rare occasions. One such instance where I use it are photos of the sky . Here autofocus often cannot find a target, and therefore I set focus to infinity. Another instance are sports photos where autofocus is too slow. Here, I often also use focus lock as an alternative. That is, I focus in advance, keep the shutter button half-pressed and wait for "the" moment.

My main application for manual focus are macro photos, because here it often happens that autofocus does not lock or finds the wrong target. Even spot AF is not of much help, but I never tried the new "mini" spot - perhaps this might improve matters...

I have focusing issues for macros not only with the A12-50 camera unit, but also with the P10 when shooting "tele macros" (macros at wide focal lengths are less critical). Here, manual focus comes to the rescue for me. Typically, I preset distance (for example the minimum distance of 7cm for the A12-50) and "focus" by moving head and camera.

 

Appendix: General Manual Focusing Methods

In the following, I describe general manual focusing methods. The sections on zone focusing was adapted from Roger Hicks' and Frances Schultz's Photo School, the one on hyperfocal distance in part from Wikipedia.

Zone Focusing

Procedure for zone focusing with a lens that has a depth-of-field scale:

This sets the lens into a "snapshot" mode that does not require further focusing.

    

Photos: Zone focusing demonstrated with a manual lens (at f4.5, range from 1.2m to 5m; left) and with an AF lens (at f8, range from about 1.2m to 5m; right)

Distance Estimation

For non-moving subjects, I simply estimate the distance of the subjects and set the distance on the lens accordingly. This is easier than one might expect, particularly when using lenses with a short focal length and middle-to-small apertures. There is also an old rule of thumb that the zone of sharpness extends to one third in front of the distance you set and two thirds beyond it.

When using a Ricoh AF lens, you can use the autofocus for estimating the distance for you, provided that autofocus finds a target. Just focus with AF and then switch from auto- to manual focus ("AF/MF"). The "AF/MF" function sets the manual focus to the distance that AF has set.

Pre-Focusing

Pre-focusing can be regarded as a variant of distance estimation, namely one for moving subjects (Roger and Frances call it a variant of zone focusing, but there is no zone here...). You set your lens to the distance at which you expect the subjects to appear and wait until they come into (pre-)focus. Typical applications are sports and action photography.

For pre-focusing with a Ricoh autofocus lens, you can first use the AF to set the appropriate distance and then switch to manual focus. The "AF/MF" function sets the manual focus to the distance that AF has set. Of course, this works only in cases where AF finds focus (for example, it may not work for sky or macro photos).

Hyperfocal Distance

According to Wikipedia, definition 1 (the one that I find more useful), the hyperfocal distance is the closest distance at which a lens can be focused while keeping objects at infinity acceptably sharp. When the lens is focused at hyperfocal distance, all objects at distances from half of the hyperfocal distance out to infinity will be acceptably sharp.

But how do I know this distance for my specific lenses without having to perform calculations and brood about which circle of confusion I would accept?

In practice, I accept the circle of confusion that the lens maker decided for (there are differences between lens makers...) and proceed in the following way:

I could confirm that I am correct at DOFmaster (Hyperfocal distance). By the way, if you proceed as described above, you can also verify that the closer depth-of-field-mark is set to about half the distance that you actually indirectly set this way, namely the hyperfocal distance.

Note that this procedure only works for lenses with a depth-of-field scale. In all other cases more effort is needed (See DOFmaster -> Hyperfocal distance)...

Also note that setting the hyperfocal distance is most useful for wide lenses with a large depth-of-field.

    

Photos: Hyperfocal distance demonstrated with a manual lens (at f8, hyperfocal distance about 1.9m, range about 0.95m to infinity; left) and with an AF lens (at f8, hyperfocal distance about 4.5m, range from about 2m to infinity; right); the AF lens is probably not set optimally

Final Word

You can mix this all up at your will: You can either decide for a distance and keep the 1/3-2/3 rule in mind, or you look for a range, which you can also manipulate so that one end is infinity...

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02.01.2012