A900 - Workflow for tripod mounted landscapes with MLU

Thanks for the replies.

When I suggested using hyperfocal it would only by be used when part of the image is at infinity. I would limit the aperture to a max of F11 and when calculating the hyperfocal I use a circle of confusion that is smaller than usually used for 35mm. When the scene does not include something at infinity, I calculate the distance to focus on using the nearest and furthest distances in the scene (I've made up a small chart for each focal length). I typically use a small rangefinder (circa 1950) that I found on eBay to find the point in the scene that is at the distance that I calculated.

Paul_o said:

When I suggested using hyperfocal it would only by be used when part of the image is at infinity.

Click to expand...

Focus at infinity than.

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http://www.libraw.org/

Your workflow would work well with the a900. Unfortunately the 24-70 doesn't have a DOF calculator. The method that Charles (first response above) describes works well. If I have any doubts about DOF, I will shoot and image focused fairly close and stopped down, then one focused one-third into the scene and then one focused toward infinitely. On the computer I'll just look at which one I like the best. I have a tripod landscape setting that I like that is set to my Custom # 1 for both the a700 and a900. Camera is set in manual mode, ISO 200, manual focus, AF-off, RAW, 2-sec mirror pre-fire, matrix meter. On the a900, you could substitute 2-sec timer for MLU and use a cable release (not the remote comander) and ISO 320 if desired.

Also, I am really trying to look at a scene and think about what can I do in the field that will lend itself to optimizing in the computer later, e.g. increasing DOF or dynamic range. In the image below of Lake Sherburne in Montana, I knew the it would be tough to get the mountains in the background and the grasses in foreground in focus. When composing the image in the field, I could see that it would be very easy to make a layer mask through the blue water reflection so that a composite image could be made with both the mountains and grasses in focus. The composite image is overall sharper that the hyperfocused image of the same scene.



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Erik H. Pronske, M.D.
http://www.pbase.com/epronske

Douglas Boyd said:

I've seen some of the posts in which this arguement is advanced based on theoretical considerations, but I have never been able to see this effect in my own pictures with the A900. Nor have I seen example pictures showing this. Do you have an example to post?
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==Doug

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Here is one example from Andrey Tverdokhleb, co-developer of RPP.

http://forum.getdpi.com/forum/showthread.php?p=103668#post103668

headofdestiny said:

Here is one example from Andrey Tverdokhleb, co-developer of RPP.

http://forum.getdpi.com/forum/showthread.php?p=103668#post103668

Click to expand...

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Okay, I looked at this example. To save time for others, this is a comparison in which the ISO320 shot is underexposed by 3 stops and the ISO200 shot is underexposed by 3-2/3 stops. The shot that is 2/3 stop less underexposed looks fractionally better. Not very convincing!

However, thanks for the link. If you look at the entire thread, it appears that I am not the only one that isn't able to see this issue. After reading this I plan to continue to use ISO100 and ISO200 with my A900 when there is good light.

==Doug

Not sure what happened to my reply text, but here is what I tried to post:

The referenced sample pictures are not convincing, but the entire thead is an interesting read. I am not the only one who is having trouble seeing an advantage to ISO320.

I did download the referenced images. The ISO320 shot was 3 stops underexposed. The ISO200 shot was 3-2/3 stops underexposed. The ISO320 with 2/3 stop less underexposure is fractionally better than the ISO200 shot.

After reading this technical thread I plan to continue to use ISO100 and ISO200 with good light on the A900.
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==Doug

Iliah Borg said:

Iliah Borg said:

When I suggested using hyperfocal it would only by be used when part of the image is at infinity.

Click to expand...

Focus at infinity than.

Click to expand...

Hi Iliah,

This runs so counterintuitive to how I learned to use hyperfocal distance when having compositions with near, middle and far subjects. I have noticed that when focusing 'hyperfocally' in these cases the subject at infinity is not sharp. Perceptually though, doesn't human vision expect far away objects to not be as sharp as close ones? I am usually very close to my 'near' subjects, so it is very important that they be sharp.

I just downloaded and am reading 'ins & outs of focus' like you suggested, but I would love to hear your thoughts on the subject as well.

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http://www.flickr.com/photos/bohlander

Douglas, being able to see the differences between ISO 200 and 320 relies on a number of factors, including workflow and the shooting scene. The problems below ISO 320 may become more of an issue in the future, as converters improve. I've noticed that so many shooters clip their blacks during processing/conversion, that the shadow problems may no be an issue for them. Regardless, while using ISO 200 vs. 320 is debatable, using ISO 100 isn't. It is the same as using ISO 160 with +2/3 EV, which isn't very useful (the extra exposure misleads us into thinking there is less noise. )

Very interesting. I won't claim to have read & digested all the equations in the last hour, but I'll definitely give this a try. I normally shoot wide (in the 16mm-> 20mm range), so if I focus at infinity and stop down only to f/8, this gives me a "disk of confusion" of 2mm -> 2.5mm which should resolve near objects just fine.

Or am I misunderstanding?

Mike
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http://www.flickr.com/photos/bohlander

mikeboh said:

but I'll definitely give this a try.

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Thank you.

mikeboh said:

I normally shoot wide (in the 16mm-> 20mm range), so if I focus at infinity and stop down only to f/8, this gives me a "disk of confusion" of 2mm -> 2.5mm which should resolve near objects just fine.

Click to expand...

An example with the cannon, right?

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http://www.libraw.org/

Here are two 100% 'near' crops taken at 16mm f/11 1/60th ISO 320, on A850 using the cz 16-35. I processed them using RPP using default settings w/ sharpening set to 0 and interp set to VCDMF.

The crop is from the bottom 1/3rd of a vertical frame

Infinity crop:
http://hornblade.smugmug.com/photos/648457925_DBCR4-L.jpg

Hyperfocal crop:
http://hornblade.smugmug.com/photos/648457969_6AYXf-L.jpg

Original infinity image (not high res):
http://hornblade.smugmug.com/photos/648458778_yQike-L.jpg

The crop is of the 'near' object. The hyperfocal image is definitely sharper as expected in the 'near'. In the middle and far range though, infinity focus clearly wins out (moreso in the far than middle, but it's still noticeable). If anyone wants me to post crops from the 'middle' and 'far' areas let me know.

This is very different than how I'm used to focusing. I need to decide if the tradeoff between near and middle/far focus is worth it. I don't really want to start focus bracketing and using Helicon . I'll give this a try in a more photographic setting (instead of my porch) next time I go shoot.

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http://www.flickr.com/photos/bohlander

mikeboh said:

I need to decide if the tradeoff between near and middle/far focus is worth it.

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Much depends on the understanding of the psychology of the viewer, perspective, and print size. Normally sharpness is compared on screen at 25-50%, mostly at 30%, but not at 100%.

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http://www.libraw.org/

Douglas Boyd said:

The ISO320 shot was 3 stops underexposed. The ISO200 shot was 3-2/3 stops underexposed. The ISO320 with 2/3 stop less underexposure is fractionally better than the ISO200 shot.

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Both shots are equally underexposed.

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http://www.libraw.org/

Iliah,

Are we looking at the same message? Here is the quote:

Iliah Borg said:

Same exposure (shutter and aperture), different ISOs.
200 left, ISO 320 right.

Shots were underexposed, so 320 was compensated for 3 stops and 200 for 3 > 2/3 in converter.

Click to expand...

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==Doug

Douglas Boyd said:

Douglas Boyd said:

Same exposure (shutter and aperture), different ISOs.

Click to expand...

Click to expand...

Yes, it clearly says "same exposure", meaning the same amount of light. In-camera amplification was stronger for ISO 320, and rendered better results. That is the whole point.

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http://www.libraw.org/

headofdestiny said:

For me, any minute difference in noise and DR of ISO 200 over 320 is negated by the blotchy shadows, and I haven't shot below ISO 320 in a long time.

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Fascinating discussion on the optimal ISO for the A900. Does anybody have an opinion on the optimal ISO for the A700?

N.