Sony Zone focusing?

[retow]

I've heard the new second gen RX100 is good to ISO 6400 - if they put a distance scale and a decent auto-ISO setup in that camera, IT could be the best street camera out there, with its deeper DOF. But they didn't include either of those things....

-Ray

I still have the RX100. Compared to the RX100, the A is on much faster and its tiny lens does not change the camera`s weight balance and handling at all, whereas the RX100 feels quite front heavy with its largish lens and not as "save" in the hand to work with. And is also much more visible in the hand. Changing settings of the A is faster and much more intuitive. And lastly, DR often is important when street shooting, and this is where the larger sensor has a clear advantage. Both have literally no shutter lag which is important for street.
With the changes discussed in this thread, the RX100 would become an even better all-rounder, but for street, I`d favor the A or Ricoh GR. The A is the best street camera for me so far.

 

[aleksanderpolo]

I remember that at f5.6 the hyper focal should be around 3m? I always set it at 5m if I want infinity focus at f5.6.

 

[flash]

That's because a lot of CoC measurements are based on a 5x7 inch print. So even viewing on your ipad will show a difference, let alone a 27 inch monitor. You're right. DOF scales are a guide, adjusted to taste.

Gordon

My experience is that DOF scales really needs to be defined better. It all depends on your expectations of sharp. Just took some test shots the other day and to me I have a hard time settling on using DOF for anything other than as a guideline. My take is that you need to focus on the important part of your composition and then maybe use a conservative DOF scale to adjust the f-stop to bring the rest of you composition into acceptable focus.

I set up the Ricoh GR to Snap Focus at 2.5m and shot at f5.6 and f11. The DOF scale on the GR indicates that at f5.6 infinity will be in focus. Well, looking at the images and comparing to the shots where focus was set to infinity I can see clear differences. Depending on the size of the exported image it's more or less obvious, but it's still there.

All the image files are tagged with the aperture used and with "snap" for 2.5m Snap Focus and "inf" for Infinity settings.

Here is the shot at f5.6 - first the smaller size:

http://thomasrisberg.com/DOF/R0000549-f5.6-snap.jpg
http://thomasrisberg.com/DOF/R0000553-f5.6-inf.jpg

Looking at the bridge in the distance I feel that the shot at infinity focus is slightly sharper.

Now with a larger file size:

http://thomasrisberg.com/DOF/R0000549-f5.6-snap-L.jpg
http://thomasrisberg.com/DOF/R0000553-f5.6-inf-L.jpg

Here it's really obvious that 5.6 isn't enough to get the distant bridge into sharp focus.

Even at f11 I can see a slight difference in sharpness at this size.

http://thomasrisberg.com/DOF/R0000551-f11-snap-L.jpg
http://thomasrisberg.com/DOF/R0000554-f11-inf-L.jpg

It gets really apparent when viewing the full size of the shots:

http://thomasrisberg.com/DOF/R0000551-f11-snap-XL.jpg
http://thomasrisberg.com/DOF/R0000554-f11-inf-XL.jpg

So, bottom line is to determine what your accepted level of out-of-focus is for the size you intend to use your pictures. And take some test shots - it really made me realize that I had to change my thinking about DOF quite a bit.

-Thomas

 

[deckitout]

Okay interesting thread but I am confused here so can anybody help me out. I am definately missing the plt

I'll use my LX7 as an example

On DOF master I inputted Camera (used LX5 as LX7 does not appear to be listed

Focal length 35 mm (I presume I set it at 35mm equivalent
selected F stop F4
subject distance 10ft

It is telling me the Hyperfocal distance is 167 ft and DOF extends from 83ft to infinity

This doesn't seem correct can anybody help me understand

Thanks Phil

 

[Ray Sachs]

The big mistake is that you're inputting the equivalent focal length (35mm), rather than the actual focal length (probably something like 6-8mm - IIRC the 24mm equivalent is actually 4.7). Take a shot at the 35mm setting and then open it in something that shows the Exif and it'll show you the actual focal length. The LX5 doesn't quite work as a stand-in either because the sensor sizes and focal lengths aren't actually the same - merely close.

The other thing with the LX7 is it doesn't actually have a distance sale - it just has a DOF scale. So you're best bet with it is to skip DOF Master and just use the scale on the camera. Slip it into manual focus, set the step zoom to 35 (or 28 or whatever you like) and adjust the focus and aperture and watch the DOF "bar" expand and contract - that bar represents your in focus "zone". The smaller the aperture and the wider the focal length, the more DOF you'll have. Theoretically, hyperfocal distance for any given combination is when the right end of that DOF bar just first hits the infinity mark. I don't know just how accurate that DOF bar is (they tend to be conservative for my use), but the LX7 has sooooo much DOF that you won't go too far wrong using it as a guide. I've used it and anything it shows will be in focus will BE in focus.

-Ray

 

[deckitout]

Ray your a star, many thanks for clearing that up

Phil