GX 100 autofocus: so which is correct?

Started Aug 18, 2007 | Discussions thread
Tom Caldwell Forum Pro • Posts: 33,635
My take on this

Guy,

You explained it very well and I think that you are right in your assumprion that Ricoh use similar focussing methods across their range on cameras (at least until the R6). Not being a technical-naming boffin I will limit myself to describing the methods of focus that are all wrapped up in one neat little package:

1. "Snap" focus or fixed-focus at about 8' or just under 3 metres - this is "fixed focus" and uses the camera's wide angle dof to bring your subject image into focus. Pressing the shutter gives near instant response as there is no focussing delay whatsoever. A variant on this is (near) "infinity" focus that I seem to recall there were threads that "complained" that this was not "true infinity" and that the best way to get "true" infiity was to put the GR-D into manual and wind the focus out until the "motor stopped". I also believe that variations on snap can be made by setting focal length manually as the focal length stays fixed when set manually - until you go back to "auto-focus". Therefore snap and infinity mode are only two fixed sub-sets of manual focus on over-ride.

2. "Full press" focus - just does the best that the camera can do with what information is has - this is pretty quick and a fair job is done - but you compromise speed against some accuracy and it may not work in all conditions.

3. "Soft-press-click" focus there are two results form this focus mode - the multiple focus indicators and the single larger focus indicator - just as Guy describes. This is slower but I have found it accurate.

4. "Macro" focus - despite what it is called this works at all focal lengths - it is quite slow and sometimes hunts a bit but because it seems "deadly accurate" I tend to use it frequently.

5. "Manual" focus when all else fails. I have been able to lock-on precisely in complete dark just using led torchlight (auto focus failed) - this can be shown in the following image:

This is a crop of the above to show that the manual focus is precise enough.

It also shows that using the GR-D at high ISO and b&w does give grain but it is the acceptable sort and does make the camera very versatile.

I find it hard to believe that Ricoh cameras need any more focus-type choices and sure there is one or more of the above that will satisfy even the most discerning.

Sure, sometimes focus can be slow, but there are alternatives for the impatient. However - blindingly fast deadly-accurate focus? ... pass me my smelling salts and my 5D ....

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Tom Caldwell

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