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Hyperfocal distance with M8 and cv 28 f 1.9


Giorgio Festa

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Dear all,

Happy new year.

Probably this is a silly question but in these days I have a doubt about the hyperfocal distance with the gear in object.

In fact, when I stop down the aperture to f8 with a focus at 3 meter, the scale distance indicates that everything in between 1.5meter to infinity shiul be in focus.

Is it correct or should I calculate the M8 crop factor (1,3) when I calculate it?

Sorry again for this doubt...

Tks

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Without going into the technicalities of circles of confusion, the diagonal measurement of the image, print viewing distance and the square root of the distance between Jupiter and Mars, there's an easy rule of thumb.

 

Use the depth of field indicators on the lens focusing barrel for the next smaller aperture stop than the one you are shooting at - that pretty much allows for the crop.

 

So if you are actually shooting at f/4.0, assume that the usable distance range is that shown between the two f/5.6 markers on the lens focusing barrel.

 

Hope that helps.

 

Mike

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It all depends on how much you enlarge your pictures. Many people find that if they use the DOF scale for one stop wider than they actually use, that gives a margin of safety. So if you stop the lens to f/8, use the DOF scale for f/5.6.

 

Another issue with the M8 is that the zone of best sharpness at middle stops may be mostly behind the point of RF focus rather than 1/3 in front and 2/3 behind as with film. The easiest thing to do is to take a few test shots and view or print the photos at the size you intend to use. Then you will know what to do.

 

--Peter

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Sean Reid has a good essay on zone focusing on his site. I share his working method, however, which is to set the lens to the distance that allows peak focus to fall on the desired subject.

 

Peak focus can only occur at one point, and then falls off to varying degrees in front or behind. One can get quite good at setting, or pre-setting, a lens to a specific distance, then stopping down as needed...or not. Lots of practice using your equipment, and looking at prints, is the best way to determine what works for you.

 

Jeff

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It all depends on how much you enlarge your pictures. Many people find that if they use the DOF scale for one stop wider than they actually use, that gives a margin of safety. So if you stop the lens to f/8, use the DOF scale for f/5.6.

 

Another issue with the M8 is that the zone of best sharpness at middle stops may be mostly behind the point of RF focus rather than 1/3 in front and 2/3 behind as with film. The easiest thing to do is to take a few test shots and view or print the photos at the size you intend to use. Then you will know what to do.

 

--Peter

 

Sorry Giorgio, Peter is exactly right - that's what I meant to say in my reply but must have been a little tired - use the depth of field settings for a stop larger than you are using.

 

Mike

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