COC - DOF - X1D Hyperfocal

[tashley]

So, one thing I noticed yesterday was that at F8 one has to place focus very carefully (or luckily) on the 30mm lens in order to get acceptably sharp foreground (and bottom corners) and yet maintain good infinity resolution.

So this morning I did some math that others might find useful

I am 5'9" tall (175cm). At that height, with the camera to my eye and held level according to the camera's built-in level, the nearest point in the frame is approximately 3 metres away (flat ground, ground level point).

Assuming I want a print that is 46" wide (in other words printed to 180DPI which will work perfectly well although it is of course always better to print at higher resolutions) and that the viewing distance is 24 inches, the required Circle Of Confusion is 23µ. That means that the hyperfocal distance is 5.55 metres.

Being phenomenally anal retentive, I took a tape measure and set it to that distance, focussed on the mark, set it to F8 and levelled it and fired away.

It doesn't quite work. It's pushing it a touch, but 6.55m does work. Now I just need to work out a way of telling the camera to focus on that distance... or of memorising that distance so well that I can always pick a point.

Hope that helps someone!

 

[MGrayson]

Tim,

Try f/11

--Matt

 

[tashley]

Tim,

Try f/11

--Matt

It's a question of honour to get it right at F8 :ROTFL:

 

[KeithL]

The trials and tribulations of lenses without distance scales.

 

[tashley]

The trials and tribulations of lenses without distance scales.

All this stuff should be possible in firmware. What I'd love is the ability to select COC from a drop down and have the camera set hyperfocal. Yum.

 

[D&A]

All this stuff should be possible in firmware. What I'd love is the ability to select COC from a drop down and have the camera set hyperfocal. Yum.

Without a distance/DOF scale on the lens barrel, a lookup table incorporated in the camera's menu, shouldn't be too hard for Hasselblad to implement via a firmware update. It only needs to be done for lenses (their focal lengths), both currently available for the X1D as well as future releases. Of course having a "cheat sheet" is in one's pocket to refer to is always an option...LOL.

Dave (D&A)

 

[JoshMerwin]

So, one thing I noticed yesterday was that at F8 one has to place focus very carefully (or luckily) on the 30mm lens in order to get acceptably sharp foreground (and bottom corners) and yet maintain good infinity resolution.

So this morning I did some math that others might find useful

I am 5'9" tall (175cm). At that height, with the camera to my eye and held level according to the camera's built-in level, the nearest point in the frame is approximately 3 metres away (flat ground, ground level point).

Assuming I want a print that is 46" wide (in other words printed to 180DPI which will work perfectly well although it is of course always better to print at higher resolutions) and that the viewing distance is 24 inches, the required Circle Of Confusion is 23µ. That means that the hyperfocal distance is 5.55 metres.

Being phenomenally anal retentive, I took a tape measure and set it to that distance, focussed on the mark, set it to F8 and levelled it and fired away.

It doesn't quite work. It's pushing it a touch, but 6.55m does work. Now I just need to work out a way of telling the camera to focus on that distance... or of memorising that distance so well that I can always pick a point.

Hope that helps someone!

I don't know the conversion for meters to feet, but can't you figure it out and lay down in front of the camera the appropriate distance, focus with the Phocus mobile app and then move out of the way and take the picture? Like this: :ROTFL:

 

[tashley]

I don't know the conversion for meters to feet, but can't you figure it out and lay down in front of the camera the appropriate distance, focus with the Phocus mobile app and then move out of the way and take the picture? Like this: :ROTFL:

You may think that's meant as a joke but it's perilously close to the truth: I choose an object that I want in the middle of the field, step 8.5 paces away, turn and focus on the object and can count on it being hyperfocally placed. It's almost as daft....:thumbup:

 

[algrove]

All this stuff should be possible in firmware. What I'd love is the ability to select COC from a drop down and have the camera set hyperfocal. Yum.

You're asking for a XF feature in an X1D body if you want hyperfocal done in camera.

 

[docmoore]

That distance is within the range of a cheap laser disto ...

https://www.amazon.com/Leica-DISTO-...F8&qid=1488551090&sr=8-1&keywords=leica+disto

The Stanley is cheaper depending upon desired max range ...

https://www.amazon.com/Stanley-STHT...coding=UTF8&psc=1&refRID=ZC9GQVCZVBGVWCBN2AZK

Very bright conditions make it hard to see the laser spot but most times it is a help.

Bob

 

[hcubell]

I don't know the conversion for meters to feet, but can't you figure it out and lay down in front of the camera the appropriate distance, focus with the Phocus mobile app and then move out of the way and take the picture? Like this: :ROTFL:

Now, that's what I call a kludge.

 

[tashley]

That distance is within the range of a cheap laser disto ...

https://www.amazon.com/Leica-DISTO-...F8&qid=1488551090&sr=8-1&keywords=leica+disto

The Stanley is cheaper depending upon desired max range ...

https://www.amazon.com/Stanley-STHT...coding=UTF8&psc=1&refRID=ZC9GQVCZVBGVWCBN2AZK

Very bright conditions make it hard to see the laser spot but most times it is a help.

Bob

I have a disto and in fact it has a built-in camera so you can actually see what you're pointing it at on screen. However, the point (for me at least) of the X1D system is that you don't have to carry a support system of other bits'n'pieces with it. If the camera has a way of determining focus distance then it should be easy to ask it to set focus to whatever one has determined as hyperlocal.

The XF system isn't all that amazing. I watched a one hour webinar in which they didn't point out that judging focus on a MacBook Pro screen was going to be different from various print resolutions, and in which I learned that after all the calibration process, you can only set one hyperlocal distance per lens and that it does not vary according to aperture. So in reality it is very simple. The math exists to start from intended print size and viewing distance, use the corresponding COC and determine for each aperture what the hyperlocal distance should be - especially when the lens is a known factor.

 

[hcubell]

I have a disto and in fact it has a built-in camera so you can actually see what you're pointing it at on screen. However, the point (for me at least) of the X1D system is that you don't have to carry a support system of other bits'n'pieces with it. If the camera has a way of determining focus distance then it should be easy to ask it to set focus to whatever one has determined as hyperlocal.

The XF system isn't all that amazing. I watched a one hour webinar in which they didn't point out that judging focus on a MacBook Pro screen was going to be different from various print resolutions, and in which I learned that after all the calibration process, you can only set one hyperlocal distance per lens and that it does not vary according to aperture. So in reality it is very simple. The math exists to start from intended print size and viewing distance, use the corresponding COC and determine for each aperture what the hyperlocal distance should be - especially when the lens is a known factor.

Completely agree. I don't see why it should be so hard to build into the firmware a Menu item that lets you press a button that would then set the focus point of the lens at the hyperfocal distance for the selected aperture for that lens and show you the range in feet or meters the near point and the far point of what will be "in focus."

 

[KeithL]

Completely agree. I don't see why it should be so hard to build into the firmware a Menu item that lets you press a button that would then set the focus point of the lens at the hyperfocal distance for the selected aperture for that lens and show you the range in feet or meters the near point and the far point of what will be "in focus."

I suggested precisely this to be incorporated into the H series many many years ago, but it never materialised.

Given that different folk have differing COC requirements I can perhaps understand why manufacturers are shy about DOF scales on lenses, but, and it's a mighty big but, why oh why no distance scales???

One of the most compelling reasons I bought into the Leica M series was for the comprehensive info available - aperture, distance focused and DOF - with a mere glance at the lens.

 

[hcubell]

I suggested precisely this to be incorporated into the H series many many years ago, but it never materialised.

Given that different folk have differing COC requirements I can perhaps understand why manufacturers are shy about DOF scales on lenses, but, and it's a mighty big but, why oh why no distance scales???

One of the most compelling reasons I bought into the Leica M series was for the comprehensive info available - aperture, distance focused and DOF - with a mere glance at the lens.

When you think about the complexity of the firmware for the drones that DJI builds, this should be child's play, and you would hope that DJI can help provide the resources to Hasselblad to implement it.
Has anyone other than Phase tried to do this sort of thing?

 

[tashley]

When you think about the complexity of the firmware for the drones that DJI builds, this should be child's play, and you would hope that DJI can help provide the resources to Hasselblad to implement it.
Has anyone other than Phase tried to do this sort of thing?

I'm not sure but if there's a distance scale on the lens or in the display, one can always make one's own COC decisions and then perform DOF calculations for various apertures either on the fly or as a cheat sheet. I use a cheat sheet with my Rodie HR40 with Alpa HPF ring / IQ180 combo and it worketh like a dream....

 

[KeithL]

I'm not sure but if there's a distance scale on the lens or in the display, one can always make one's own COC decisions and then perform DOF calculations for various apertures either on the fly or as a cheat sheet. I use a cheat sheet with my Rodie HR40 with Alpa HPF ring / IQ180 combo and it worketh like a dream....

I'm not at all sure I'll be buying into any new system that lacks the minimum of distance scales on lenses.

 

[MGrayson]

When you think about the complexity of the firmware for the drones that DJI builds, this should be child's play, and you would hope that DJI can help provide the resources to Hasselblad to implement it.
Has anyone other than Phase tried to do this sort of thing?

Leica's S(007) displays near and far focus distances.

--Matt

 

[D&A]

I'm not sure but if there's a distance scale on the lens or in the display, one can always make one's own COC decisions and then perform DOF calculations for various apertures either on the fly or as a cheat sheet. I use a cheat sheet with my Rodie HR40 with Alpa HPF ring / IQ180 combo and it worketh like a dream....

I was sort of making a sort of a joke in my previous post above, but thats basically what I suggested as the easiest work around for the time being. Namely a cheat sheet (laminated and foldable). Used to do this with lenses that lacked DOF scales on the barrel.

Cell phone app/spreadsheet is another way to go. Heck, a middle of the night phone call (while shooting) to one of the Hasselblad lens designers is always an option .

Dave (D&A)i

 

[siddhaarta]

Leica's S(007) displays near and far focus distances.

--Matt

Which is a very nice feature, which Hasselblad could implement easily.

Problem of the Leica S implementation is that they apply a (to me) secret (but apparently quite conservative) CoC which cannot be altered. Funny thing is that the DOF values on the datasheets of the lenses do not correspond to the implementation in the camera. Seems they applied different CoC.