Setting Hyperfocal distance

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A_S

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Andrew
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Hi,

I took this this afternoon, after calculating the hyperfocal distance (95cm), I set it by using Magic lantern to read off the aprox focal length in live view and verifying this on the distance scale:


Forth Bridge from North Queensferry by Andrew_S84, on Flickr

After getting home I was a little disapointed to see the bridge, boat isn't very well focussed.

What techniques do others use to physically dial in the hyperfocal distance to their lens?

I've had a bit of a concern about the way I'm setting it for a while to be honest.

Andrew
 
Hi Andrew.

I'm a relative newb here and very much amateur but ill be dirt to answer with the risk of my answer being totally blown out of the water

Judging by the smoothness of the water and blur in the clouds in gonna hazard a guess that you've used some sort of ND filter. If this is the case and you've done a long exposure then the boat will not have been still throughout and therefore it will not be the focus that's the problem and rather the movement

I hope this is a starting point for you. I'm only just up the road from the bridges so may give this shot a try myself.

Derek
 
Thanks

Will have a look at the angle and see if needs straightening - I have to say I didn't think it was critical to this one.

Yes i was using an ND - that would explain the boat - seems obvious now...

However that does not explain the bridge - if you zoom in on the full size version you will see what I mean - I seem to have missed focussing to infinity as the bridge gets progressively softer to the right of the anchor and isn't exactly wonderfully focused to the left either
 
Slight tripod movement during the long exposure maybe?
 
A_S said:
Thanks

Will have a look at the angle and see if needs straightening - I have to say I didn't think it was critical to this one.

Yes i was using an ND - that would explain the boat - seems obvious now...

However that does not explain the bridge - if you zoom in on the full size version you will see what I mean - I seem to have missed focussing to infinity as the bridge gets progressively softer to the right of the anchor and isn't exactly wonderfully focused to the left either
Click to expand...

I noticed some of the girders (cross sections in the middle) were blurred but the movement of the clouds suggest a windy day and the bridge will have slight movement too. They are designed to.

The other option would be to take a single image of the bridge first and then take a long exposure as you did and combine the 2 images.

John
 
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A_S said:
Will have a look at the angle and see if needs straightening - I have to say I didn't think it was critical to this one.
Click to expand...

Mother nature provides a fantastic spirit level and it's the water line ;)
 
I see that you took the shot using your 10-22 mm lens set at 12mm at F8 an 164"
You seem to have a combination of problems
At that setting your lens suffers from considerable optical distortion which could be corrected in software.
looking at your original file at 100% shows all parts of the bridge and even the top part of the anchor to lack focus as do the sides of the foreground.

At the F8 aperture this is not something I would expect, as most lenses are at their best at around that stop.

There is a degree of camera shake which always effects the image more badly at greater distances.
the hyper focal setting is unlikely to be far out as the main ring on the anchor seems to be the focus point. It must be remembered that Focus is only ever at its sharpest at one point, and falls off both in front and behind, Hyperfocal setting is just the best compromise that can be made at the set aperture.

Saying all that I do not find the result in this case to be acceptable.
I would question the quality of this particular lens.
I suspect that there was some vibration in the camera/tripod
( In such long exposure situations you must turn off the the anti-shake feature in the lens or the image will "wander" during exposure. Though I do not believe this lens has that feature anyway.)
The shot could do with having the Geometric distortions corrected.

The Idea and the concept are excellent.

An alterative concept would be to have the bridge more out of focus, and the anchor totally sharp as it would simplify the image..
 
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I tend not to bother with DOF and HFD tables. My usual approach is to use manual focus while I'm zoomed in to the max in Liveview. With the lens stopped down I can then adjust the aperture and focus point to give me the result I want.
 
For Canon users only ( or other cameras that have depth of view preview button).

Place camera on tripod. Set the lens to manual. Decide what aperture you want to use ( usually f11 etc but not too large that diffraction starts to effect sharpness) Focus on infinity. Switch on live view and zoom in at maximum enlargement ( normally 10X) on some very distant object. Depress the dof preview button. Wind the focus gently away from infinity until the distant object just starts to appear fuzzy. Nudge back a bit until distant object appears to be in focus. Release dof preview button. Distant object should now appear out of focus BUT will be in focus when camera closes down aperture automatically on firing. Camera is now set to hyperfocal point. Take shot.
With practice this process should take less than one minute to complete.
Hope this helps
James
 
Thanks - the advice and critique is welcome. If it is the lens (until proven otherwise I would still question whether it is more my technique) then I wonder what my options are - it is less than 6 months old so I presume it is still under warranty - it is just proving that it is optically flawed. What is the best way to test this?

I will have to try the 2 other suggested methods too
 
I would take a series of shots absolutely square on to a large building with the lens zoomed to different settings. and examine the results taken at different apertures at 100%.
Certainly by f8 the field should be fairly even across the image. one side should be equal in quality to the other, but may be slightly softer than the centre.
Pincushion or barrel distortion is not a problem as it is easily corrected.

You want to be able to rely on evenness of quality across the field with no major differences. Zooms do vary to some extent over their range, but if you get unexpected changes between shots or side to side, something is probably wrong.
 
Thanks, when the weather improves I will get out and test it on the house.

Thanks for the tip on the perspective changes, I've always just let camera raw apply the auto perspective adjustments - I've now changed the bridge tower perspective, foreground a little and re-uploaded. I have to say not my area of expertese (correcting) but it will improve with time.
 
jbw said:
For Canon users only ( or other cameras that have depth of view preview button).

Place camera on tripod. Set the lens to manual. Decide what aperture you want to use ( usually f11 etc but not too large that diffraction starts to effect sharpness) Focus on infinity. Switch on live view and zoom in at maximum enlargement ( normally 10X) on some very distant object. Depress the dof preview button. Wind the focus gently away from infinity until the distant object just starts to appear fuzzy. Nudge back a bit until distant object appears to be in focus. Release dof preview button. Distant object should now appear out of focus BUT will be in focus when camera closes down aperture automatically on firing. Camera is now set to hyperfocal point. Take shot.
With practice this process should take less than one minute to complete.
Hope this helps
James
Click to expand...

Thanks James, will try this soon.
 
download DOF master for your phone.
 
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