Sony Zone focusing?

f1.8--------------------18.5 feet
f2.8--------------------11.7 feet
f4------------------------8.3 feet
f5.6--------------------- 5.9 feet
f7.1----------------------4.7 feet

Ray, it's probably just that I haven't made this as clear as I should have...

At 28mm (and working in feet), if the desired aperture is, say, f/5.6, then the calculation is 33/Av, or 33 divided by 5.6 = 5.89 feet. This, (with rounding errors acknowledged) agrees with your figures from Dofmaster above. Same applies if the aperture is f/4... i.e. 33 divided by 4 = 8.25 feet, and so on.

So, I think that we're on the same wavelength, but I guess that I haven't been expressing myself too well... my apologies for that!:)
 
Ray, it's probably just that I haven't made this as clear as I should have...

At 28mm (and working in feet), if the desired aperture is, say, f/5.6, then the calculation is 33/Av, or 33 divided by 5.6 = 5.89 feet. This, (with rounding errors acknowledged) agrees with your figures from Dofmaster above. Same applies if the aperture is f/4... i.e. 33 divided by 4 = 8.25 feet, and so on.

So, I think that we're on the same wavelength, but I guess that I haven't been expressing myself too well... my apologies for that!:)

Oh, OK, got ya!

Sounds like we're in the same place, but I didn't see the instruction to divide by the aperture, or just mis-read it. In any case, if Tom is just working with the 28mm equivalent, its probably easier just to know two or three actual values for the corresponding apertures and then just run with it. Thanks for the clarification...

-Ray
 
Tom, no offense to Porchard, but I just don't think those numbers are right. If you shoot at the 28mm equivalent (the actual focal length is 10.4), your hyperfocal distances, according to DOF master, are approximately (I say approximately because they don't have 10.4mm available as a focal length, so I had to use 10.5):

f1.8--------------------18.5 feet
f2.8--------------------11.7 feet
f4------------------------8.3 feet
f5.6--------------------- 5.9 feet
f7.1----------------------4.7 feet

I wouldn't see any reason to shoot beyond f7.1 with this camera, probably wouldn't go past f5.6

So, at f5.6 in good light, you focus at six feet (easily done for most adults, by focussing from somewhere around the top of your head or a few inches higher or lower - depending on your height - to the ground), and everything from about 3 feet to infinity is in focus. Using the previous numbers, I'm not sure where 10 meters (or about 30ish feet) as a hyperfocal distance comes from - even wide open at f1.8 its well short of that at 18.5 feet. And even if it WAS at 30 feet, you wouldn't want to use that because it would mean that everything from about 15 feet to infinity would be in focus. Most of your shots on Flickr are taken of subjects WAAAAAAY closer than 15 feet. I'd say that some of them were closer than 3 feet, so even using the hyerfocal distance of 5.9 feet at f5.6 might not always get you close enough, although it generally would. If you focussed at 4 feet at f5.6, you'd have everything from about 2.4 - 12.5 feet in focus, which might work better for you on some of your shots. But, for heaven's sake, please don't try to focus at 30 feet!!! First of all, its nearly impossible to estimate, and second of all its just waaaaay too far, even if it was right which I can't see how it is.

Again, I would put the emphasis on a focus distance you can easily estimate. I think six feet or two meters is a good place to work from. Most adults can estimate this easily by holding the camera at about the level of the top of their head or slightly above, and using auto-focus to focus on the ground. At f5.6, you're pretty much AT hyperfocal distance and you've got from 3 feet to infinity in focus - so just about EVERYTHING except extreme close up is in focus. And in lower light, if you need to go down to f3.5 (which you can use at ISO 3200 and still maintain pretty reasonable shutter speeds - 3200 still looks OK on the RX100, especially in B&W), you'll have a zone of focus from about 3.6-17 feet. This is still a very useful zone for an awful lot of street shooting.

Zone focus is a hugely useful and effective tool, but you have to have the right numbers or at least very close to the right numbers. If Porchard can show me how his numbers work, I'll be happy to listen, but using DOF Master, I honestly don't see how he came up with them. If you want to do some of this for yourself, you should familiarize yourself with DOF Master - its got a VERY easy online calculator and the RX100 is one of the many cameras in its database that you can choose from. The thing you have to remember is to use the ACTUAL focal length, NOT the equivalent focal length. The actual range of the RX100 is 10.4mm to 37.1mm, NOT 28-100mm. Here's the website to get started, if interested:

Online Depth of Field Calculator

-Ray

Oh man. This is just what I needed. Great info. I can't wait to try this out. Many thanks for this. I am telling you I have looked all over the web and the only answer to the RX100 HFD zone focus question is being answered right here in this thread. Wonderful.

I am understanding a seemingly complicated subject thanks to you fine folks.

Also....the DOF calculator is terrific. Thanks for that as well.
 
When I used my old Olympus E-PL1 and 20mm lens on the street I would just pre-focus on the ground (using AF) at an assumed distance-to-subject where I figured I would take the shot and then wait for the right moment. There were no hyperfocal distance of DOF calculations involved.
 
When I used my old Olympus E-PL1 and 20mm lens on the street I would just pre-focus on the ground (using AF) at an assumed distance-to-subject where I figured I would take the shot and then wait for the right moment. There were no hyperfocal distance of DOF calculations involved.

There are a lot of ways to shoot on the street - zone focus is only one. But if its the one you prefer, you kind of have to know that stuff. The good news is you really only need to remember one or two settings for any given focal length/camera. I shoot nearly everything at about 28mm on APS, so I just have to remember a couple of settings, which I've got pretty much down to the level of DNA at this point. With a distance scale on the lens or in the camera, its very very easy. Without one, its a bit more of a pain in the butt.

-Ray
 
Believe it or not but apart from the RX100 and RX1, my favorite street camera is the one that I carry all the time with me and its the waterproof SONY Xperia ZR phone that takes superb pictures with its 13MP sensor. It has touch focus and shutter so all I do is basically touch the subject to focus and shoot.
 
The more I read about it the more I want to try it. The new Ricoh GR with it's tiny size and snap focusing could be the perfect camera for my style of shooting.
 
The GR and the Nikon A are both kind of miraculous little cameras. Not as small as the RX100, but pretty close. Much better DR and low light and both infinitely better setup for zone focus.

BUT...

They both have more limited DOF than the RX100, so you need to stay on top of that.

I have the Nikon and have shot extensively with the GR and they're phenomenal street cameras. The Ricoh makes it easier to use zone focus (they call it 'snap' focus, but it's the same thing), the Nikon makes it easier to nail the exposure - both are a pleasure to shoot with.

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
 
But then one should be able to stop down GR/A more to achieve the same DOF as RX100? f4 on GR/A should be equivalent to f2.4 on RX100 in terms of DOF as well as light gathering ability and noise performance (as GR/A has larger sensor area)?
 
But then one should be able to stop down GR/A more to achieve the same DOF as RX100? f4 on GR/A should be equivalent to f2.4 on RX100 in terms of DOF as well as light gathering ability and noise performance (as GR/A has larger sensor area)?

Right, but the second gen RX100 is reputed to do quite well at 6400, which is about the limit of what I'm comfortable using on the A or the GR. So, if its a legit 6400 and uses comparable exposure as the other two cams, then it could use the same aperture/SS combination at a given light level but get more DOF. or a wider aperture and faster SS and get the same DOF but faster shutter. A non-issue in good light but it could be even better in low light. Not that the GR/A aren't already great in low light, but I'd take another stop if I could get it.... But not if the shooting characteristics remain as they are.

-Ray
 
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

If my RX100 had more leeway on the auto-ISO it would be a dream come true. I would love to be able to set any minimum shutter speed I wanted. Then the ISO could go wherever it wanted. I wouldn't give it a thought. I shoot auto-ISO now but have to use shutter priority to get sharp photos cause I'm always moving (and so are most of my subjects). Once I get the zone focusing technique down I'll be golden.

What's the smallest camera that allows you to set a minimum shutter speed. I would use apature priority at f/5.6 or f/8 and ride auto-ISO all day long. With a minimum shutter speed of 1/500th of a second. That would be sweet. I can do it with my 5D Mark 3 but that ain't exactly tiny. I wish Sony would offer this.
 
I've read somewhere that the sensor in Sony's small sensor is more efficient than their APSC sensor. So it is quite probable that at equivalent DOF (e.g. RX100 f2.4 vs GR/A f4), the RX100 would have better noise performance, but it would be quite incredible if it can overcome a 180% difference in sensor size to make the ISO6400 comparable.

Right, but the second gen RX100 is reputed to do quite well at 6400, which is about the limit of what I'm comfortable using on the A or the GR. So, if its a legit 6400 and uses comparable exposure as the other two cams, then it could use the same aperture/SS combination at a given light level but get more DOF. or a wider aperture and faster SS and get the same DOF but faster shutter. A non-issue in good light but it could be even better in low light. Not that the GR/A aren't already great in low light, but I'd take another stop if I could get it.... But not if the shooting characteristics remain as they are.

-Ray
 
If my RX100 had more leeway on the auto-ISO it would be a dream come true. I would love to be able to set any minimum shutter speed I wanted. Then the ISO could go wherever it wanted. I wouldn't give it a thought. I shoot auto-ISO now but have to use shutter priority to get sharp photos cause I'm always moving (and so are most of my subjects). Once I get the zone focusing technique down I'll be golden.

What's the smallest camera that allows you to set a minimum shutter speed. I would use apature priority at f/5.6 or f/8 and ride auto-ISO all day long. With a minimum shutter speed of 1/500th of a second. That would be sweet. I can do it with my 5D Mark 3 but that ain't exactly tiny. I wish Sony would offer this.
The Nikon A and the GR both do. The GR only allows you to set the minimum up to 1/250 - the Nikon allows it to be set as high as 1/1000. This difference is the biggest reason, and ultimately the deciding factor in why I bought the Nikon. If you're OK with 1/250, I'd probably recommend the GR. two of the Fuji models, the X100s and XM1 have a minimum shutter speed but theirs only goes up to 1/125. And they aren't nearly as small as the GR / A.

In all of these cams, once the max ISO you designate is reached, if additional light is needed, the shutter speed will then come down as much as needed for an adequate exposure. I love this logic - it's exactly what I'd do if I was setting it manually. But I like a faster shutter speed than 1/250 for street shooting - between my movements and the subject's, I get too many blurred shots. At 1/500, I pretty much never do.

-Ray
 
I've read somewhere that the sensor in Sony's small sensor is more efficient than their APSC sensor. So it is quite probable that at equivalent DOF (e.g. RX100 f2.4 vs GR/A f4), the RX100 would have better noise performance, but it would be quite incredible if it can overcome a 180% difference in sensor size to make the ISO6400 comparable.

I'd like to try it myself. I had an RX100 for a while and it was VERY good at 3200 and just about usable at 6400 - probably already ok for a lot of street shooting. If the new one is notably better at 6400, it's probably very close to the GR/A. Good enough, in any case.

-Ray
 
The Nikon A and the GR both do. The GR only allows you to set the minimum up to 1/250 - the Nikon allows it to be set as high as 1/1000. This difference is the biggest reason, and ultimately the deciding factor in why I bought the Nikon. If you're OK with 1/250, I'd probably recommend the GR. two of the Fuji models, the X100s and XM1 have a minimum shutter speed but theirs only goes up to 1/125. And they aren't nearly as small as the GR / A.

In all of these cams, once the max ISO you designate is reached, if additional light is needed, the shutter speed will then come down as much as needed for an adequate exposure. I love this logic - it's exactly what I'd do if I was setting it manually. But I like a faster shutter speed than 1/250 for street shooting - between my movements and the subject's, I get too many blurred shots. At 1/500, I pretty much never do.

-Ray

I wonder why Sony doesn't offer this in a firmware update for the RX100. Maybe it can't be done.
 
Thank you. You are absolutley correct. I know this and I still made a fundemental mistake and didn't read my own stuff carefully before posting. Of course the greater level of enlargement gives the impression of reduced DOF not increased. From the same spot with the same lens and aperture the smaller sensor has LESS apparent DOF. Generally smaller sensors show more DOF because the focal length is changed to get the same framing. My appologies for any confusion caused by my own laziness.

Gordon


I think it is the opposite?

Plugging in the number to the DOF calculator, for example 50mm f1.4 at 10meter.

The DOF for FF at f1.4 is around the DOF for APSC at f2.1. That means the DOF marking for 1.4 on a FF lens would be applicable to the DOF at f2.1 when the lens is used on APSC.

This sounds counterintuitive, but that's because most of DOF discussion is comparing two lens with different actual focal length on different sensor (e.g. 18mm on APSC vs 28mm on FF), not the same lens on different sensor.
 
I wonder why Sony doesn't offer this in a fireware update for the RX100. Maybe it can't be done.

I just don't think it's a priority to them. Or to many, for that matter. For street shooting, it seems like a huge advantage to me (as does zone focus, which Sony doesn't put any emphasis on either), as I think it might for sports shooters and maybe wildlife photos. But for most of the general purpose use a camera like the RX100 gets, it doesn't really matter. And I just don't think Sony has it on their radar.

-Ray
 
I just don't think it's a priority to them. Or to many, for that matter. For street shooting, it seems like a huge advantage to me (as does zone focus, which Sony doesn't put any emphasis on either), as I think it might for sports shooters and maybe wildlife photos. But for most of the general purpose use a camera like the RX100 gets, it doesn't really matter. And I just don't think Sony has it on their radar.

-Ray

This is so true, in so many ways. Any "serious" shooter using most cameras will run in to a lot of their limitations. We're lucky to have Ricoh that seems to cater more to the street shooters preferences. Most large manufacturers target the mass market. I'm using a Nikon Coolpix A and it just happens to meet some of my criteria making its handling usable for me but far from perfect. I don't expect Nikon to change anything going forward since I'm most likely not the target audience. So we learn to live with what the cameras offer and we'll keep our eyes out for the next thing that brings us closer to what we really want :).

-Thomas
 
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
 
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