Hyperfocal distance and Hasselblad lenses

[jools230575]

Morning (or afternoon) all, depending on your time zone

A quick question for those Hassie users who have been using them since the year dot.

I know how to set up my lenses on my Hassie for the hyperfocal distance. However, it seems that everything is not in focus when I do this. I'm talking stuff that is a few meters away on a 50mm lens at F22. It only seems to go into focus when I place the infinity symbol on the marker.

Any advice on this? It's the same with my 80mm and 150mm.

Thanks

Jools

[Dick Roadnight]

Morning (or afternoon) all, depending on your time zone

A quick question for those Hassie users who have been using them since the year dot.

I know how to set up my lenses on my Hassie for the hyperfocal distance. However, it seems that everything is not in focus when I do this. I'm talking stuff that is a few meters away on a 50mm lens at F22. It only seems to go into focus when I place the infinity symbol on the marker.

Any advice on this? It's the same with my 80mm and 150mm.

Thanks

Jools

I suggest you read "The ins and outs of focus" by Harold Merklinger, which was available for free download.

He recommends focusing beyond (nearer to infinity) than convention or hyperfocal, and it seems that this is what you have found, and it is what I have found.

[jools230575]

Thanks for that. I will hunt it down!

I have to say that when using the hyperfocal distance for my Canon 5D Mark II and associated lenses, if I am on F22 I tend to focus on the point for F16. I usually end up with everything incredibly sharp!

[Doug Peterson]

Thanks for that. I will hunt it down!

I have to say that when using the hyperfocal distance for my Canon 5D Mark II and associated lenses, if I am on F22 I tend to focus on the point for F16. I usually end up with everything incredibly sharp!

If you shoot a Canon at f/22 nothing will be tact sharp - you are deep into diffraction by f/22 on a 5D2. Conveniently though everything will be equally unsharp, which is the definition of hyperfocal! :-)

Do some reading on diffraction and/or take a series of pictures focused at infinity at f/8, f/11, f/16, and f/22 with your Canon to see what I mean.


Doug Peterson (e-mail Me)
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[jools230575]

OK, slight error on my part. I am fully aware of diffraction and the consequences of shooting at F22. It was a bad example to use going for F16 to F22. Really, I should have done F8 to F11 or F5.6 to F8.

Depending on what I am shooting will depend on aperture used. If I am shooting for a library I tend to make it F8 or F11 so as to get the best out of my lenses.

[Doug Peterson]

OK, slight error on my part. I am fully aware of diffraction and the consequences of shooting at F22. It was a bad example to use going for F16 to F22. Really, I should have done F8 to F11 or F5.6 to F8.

Depending on what I am shooting will depend on aperture used. If I am shooting for a library I tend to make it F8 or F11 so as to get the best out of my lenses.

Gotchya. Hope you didn't read my comment as snide - some people aren't aware of diffraction and I like to point it out when that seems to be the case as it can make a big difference!

Back to your original question: different lens systems are marked for hyperfocal for different film/digital resolutions. A Hasselblad 500 series lens is (I'm making a very well founded guess here - I've never spoken to a lens designer of a Hasselblad 500 series lens) marked for hyperfocal based on the amount of detail possible to capture on a good (but not the best ever) film and optically enlarged. So if you for instance placed an Aptus-II 12 on a Hassy 500 (which is an 80mp back with no AA filter) then you would need to be much more conservative with your placement of focus than the made-for-film hyperfocal marking would indicate.

Plus individual lenses have different tolerances (precise placement of infinity, exactness of the size of the aperture when set to f/11) both when they are made and due to wear/tear/temperature. Add to that the need to establish what "acceptably sharp" means - one mans "tact" sharp is another man's "slightly out of focus" and is another man's "completely unacceptable". The only surefire way to establish the specific hyperfocal point for your system is to test each lens at your desired shooting aperture (tethering makes this a LOT easier) and find the last point at which infinity is acceptably sharp (in your opinion and for your use).

Doug Peterson (e-mail Me)
__________________

Head of Technical Services, Capture Integration
Phase One Partner of the Year
Leaf, Leica, Cambo, Arca Swiss, Canon, Apple, Profoto, Broncolor, Eizo & More

National: 877.217.9870  |  Cell: 740.707.2183
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[jools230575]

Doug, I took no offence at all 

It was only earlier this year that HFD clicked with me. I'm not sure why as it is not exactly difficult. Diffraction is another thing. I came across this last year when trying to get onto Alamy. I was shooting everything at F22 and they kept coming back with rejections. Image was too soft. A kind soul pointed me to the wonders of diffraction.

The Hassie lenses are better marked with the aperture and DOF. However, as I said in my earlier post, I am not sure how much I should believe what is on the lens.

[Dick Roadnight]

Using a 6 micron pixel, 10 micron circle of confusion yardstick, if you use F22 you thow away 3/4 of the res you pay for.

This is a 100% crop from a 300mm shot, f20, MLU, 50 ISO... you can almost read number plates at 550m, but it is not sharp, and it is only "as sharp as it gets" from about 50m to 400m, @ COC = 40 microns, which agrees with

Rags DOF

This illustrates the need for movements or DOF merge for this type of shot.