Problem: hyperfocal distance or lens quality?

[Nigel Johnson]

Dave

I fully support DarkPenguin's comment about focusing on what you want sharp.

It would be worthwhile for you to read the articles on Luminous Landscape by Gary Ferguson entitled Focusing in the Digital Era - Part One and Focusing in the Digital Era - Part Two. The technique of "Infinity Focus" described in Part Two and the linked pages by Harold Merklinger could well be applicable to your problem. Quoting from the Part Two, but changing the values to match your 23 mm focal length:

Set the lens to infinity then divide the focal length of the lens by the aperture. This will give you, in millimeters, the subject resolution limit from the far distance to right in front of the camera. For example, say you are using a 23 mm lens focused on infinity, and the aperture is f/8, then 23 over 8 is three (give or take). Now any object in the scene larger than 3 mm will be identifiable, provided it’s within the resolution capabilities of the lens and sensor.

I hope that this might be of use.

Nigel Johnson

[Tim Gray]

There's no free lunch.  At f22 you are introducing softness due to diffraction.  Also if your expectation aren't being met, just choose a smaller COC.   The "traditional" 35mm .030mm isn't intended for the kind of pixel peeping that digital seems to incent.

[dbe4876]

Based on Nigel's recommended reading, I poured over the two-part article referenced "Focusing in the Digital Era." I went back out to the local swamp where, I've been doing most of my shooting lately, to try out the referenced "Infinity Focus" technique. I took the shots after work (around 6pm), so not the best light. But, I wasn't trying to take nice pictures as much as put the infinity focusing to the test. After setting up the Canon 30D and Tamron 17-50mm f/2.8 on a sturdy tripod and attaching a cable release, I set the lens to 17mm, put it in manual focus mode and moved the focusing ring to the infinity marker. With the camera set to AV mode, I shot at f/11, f/13, f/16, and f/22. I was done in less than five minutes, but shot the bull for another fifteen or so with a fellow shooter who was curious about what I was up to  

Attached is a Word doc where I've put the 100% frames in quad arrangements so you can compare the results. I copied four quadrants from each of the four images to compare with each other. If I knew how to embed them on this page in a similar manner, believe me I would have. Anyway, I think you can (hopefully) open the Word doc and review the results for yourselves.

[You can also view them, perhaps a bit easier, at my SmugMug gallery here]

After squinting over the images for an hour or so I have come to the conclusion that the f/11 setting gives the best result at 17mm with this lens. Of course, results will vary at other focal lengths (don't even think of asking me to go back and shoot at 23mm, 28mm, 35mm, and 50mm!!)

I'm still not sure yet whether this method beats using the hyperfocal method. Okay, clearly it beats hyperfocal for the backround (far distance), and there is clearly more definition in the marsh grasses (mid-distance) than in my hyperfocal shots, but my gut tells me it's not winning in very close quarters (though 2 outta 3 ain't bad - why does that make me think of Jack Nicolson?  ). Well, I won't know until I try both methods in the field during one shoot when I'm trying to get some seriously good images. Time will tell (okay, call me a skeptic!     ).

Oh! Here is the f/11 image with the areas under study outlined...

[martin.storz]

Don't try to use a APS-Sensor Camera as an replacement for a big format camera!

Don't examine your pictures with 100% on a screen - this is not the industrial standard to proof sharpness. (Maximum for APS is 50%, FF-Senor at 25%)

Make a print, size 8x11, look at the print, distance about 40 cm, and you will see, it's a nice sharp picture!

And if it looks nice and sharp, it will look nice and sharp at every format you can print - if you don't use a microscop to look on.

And this is, what Canon/Tamron gives you for your money, not more, not less.

Try to keep technical aspects in the background, you do no scientist work! You photograph!
Look instead on the scene and the light!


Greetings

[dbe4876]

Don't try to use a APS-Sensor Camera as an replacement for a big format camera!

Don't examine your pictures with 100% on a screen - this is not the industrial standard to proof sharpness. (Maximum for APS is 50%, FF-Senor at 25%)

Make a print, size 8x11, look at the print, distance about 40 cm, and you will see, it's a nice sharp picture!

And if it looks nice and sharp, it will look nice and sharp at every format you can print - if you don't use a microscop to look on.

And this is, what Canon/Tamron gives you for your money, not more, not less.

Try to keep technical aspects in the background, you do no scientist work! You photograph!
Look instead on the scene and the light!
Greetings
[a href=\"index.php?act=findpost&pid=109312\"][{POST_SNAPBACK}][/a]

Thanks Martin. I very much appreciate your astute and succinct feedback  

[howiesmith]

Photography is part art and part science.  I like to think of it as science that can be used to produce art.

If you don't think photography is part science, look at your electronic camera, all its options, its len(es), the computer and software you use to maniplate iamages, the printer used to make prints, etc.

I would urge you to learn what all that stuff is doing, even when on auto.  Understand how your camera works.  That includes depth of field.  Understand it and then using it will be much easier, repeatable and enjoyable.  I think in the original post, you said you were experimenting with hyperfocal distance.  That is good, but should you know what it is and how it works before you can do a meaningful experiment?

And then you can get into art and how to make good images reliably and repeatably.

[dbe4876]

Photography is part art and part science.  I like to think of it as science that can be used to produce art.

If you don't think photography is part science, look at your electronic camera, all its options, its len(es), the computer and software you use to maniplate iamages, the printer used to make prints, etc.

I would urge you to learn what all that stuff is doing, even when on auto.  Understand how your camera works.  That includes depth of field.  Understand it and then using it will be much easier, repeatable and enjoyable.  I think in the original post, you said you were experimenting with hyperfocal distance.  That is good, but should you know what it is and how it works before you can do a meaningful experiment?

And then you can get into art and how to make good images reliably and repeatably.
[{POST_SNAPBACK}][/a]

Yes, I agree with learning the technical. I think it empowers your creative side. I recently watched a PBS show about [a href=\"http://www.jimbrandenburg.com/flash/index_flash.html]Jim Brandenburg[/url], who undertook an amazingly creative journey when he determined to shoot one image per day for 90 days. This ultimately led to his book "Chased by the Light." As I watched the video about Jim's photographic adventure it was not lost to me that one of the reasons he could do so well with one image per day was the fact that he had full command over the technical side of things. That, combined with twenty years experience as a photographer for The Geographic, meant he could be fairly certain his one shot per day would be technically correct.

Being a software test analyst I do tend to get bogged down in the technical sometimes (like a dog with a bone  ). In my March 26th post I said,

don't even think of asking me to go back and shoot at 23mm, 28mm, 35mm, and 50mm!!

But, I know that at some point I will do just that. Learning that f/11 is my best stop for infinity focus at 17mm is valuable information! And knowing what the best f/stop is at the other major focal lengths, and thus having a thorough understanding of my Tamron 17-50mm lens, will also be a valuable learning experience. There's nothing that helps my ADD brain remember quite so well as getting out and doing, and then coming back and analyzing, and coming to that place of "ah ha!"

Still, I do like Martin's reminder "look on the scene and the light." It reminds me of what occurred last Saturday. I got up before sunrise and went back to my favorite swamp (it's just six blocks from my house). But it was a foggy morning, so no hyperfocal experiments that day. I soon realized however that it was still a very photographic moment, so I setup the equipment and began snapping off shots. I came away with this one...
[a href=\"http://dbe.smugmug.com/gallery/2634534#139205462-L-LB\" target=\"_blank\"]

[Ben Rubinstein]

Looks to me that you are bumping into the resolution limits of what your camera and lens are capable of, not out of focus problems per se. You have a lot of very fine detail that I would consider too much for an 8 megapixel camera with consumer lens. Hell, even my 5D would have problems resolving enough of those scenes for a large print viewed close up. You will bring back some of the detail through careful sharpening but as someone said above, these kind of scenes are LF territory if you want microscopic detail I'm afraid.

[dbe4876]

Some six months later, I am revisiting this thread as a result of noting that a number of folks have regularly clicked into the example images I embedded, which are linked to my SmugMug site.

There have been quite a few additional images taken since I began this post back in March. In June, I took my first photographic vacation/personal workshop out to Yellowstone National Park, by way of South Dakota's Badlands, Crazy Horse and Rushmore monuments, and Devils Tower in Wyoming. The "snap shots" of my trip can be found in a SmugMug gallery here, while my more serious efforts in post processing can be found at my photo.net gallery here.

Through additional "practical research" (getting out and shooting purposefully over a variety of f/stops at each major focal length), I can report the following for my Tamron 17-50mm f/2.8 lens:

@17mm - Infinity focus is best - Acceptable range is f/5.6 - 13. Best at f/8

@24mm - Hyperfocal and/or Mid-focus is best - Acceptable range is f/8 - 16. Best at f/13 * Infinity focus is also acceptable, but not as sharp, f/8-16. Best at f/13.

@35mm - Hyperfocal and/or Mid-focus is best - Acceptable range is f/13 - 20. Best at f/16. * Infinity focus is also acceptable, but not as sharp, f/16 - 22. Best at f/20.

@50mm - Hyperfocal and/or Mid-focus is best - Acceptable range is f/13 - 20. Best at f/16. (but it's obvious you're not going to get crisp foregrounds here)

As you can see, when I shot landscapes at 17mm and followed the old adage of high f/stops (e.g., f/22), I was really working against myself. I quickly recognized that as a non-plus, and began shooting more often around f/13, but even then I was only *approaching* good DOF, and I missed the best f/stop of f/8 altogether. (obviously, this data only applies to the Tamron 17-50mm f/28 lens). But, there seems now to be some basis to the view that each lens has its own set of "sweet spots" in terms of focal lengths and f/stops that provide the best DOF, and it turns out this is also dependent on the method of focusing used.

For wide angle lenses at their widest setting infinity focus wins hands down. But once you start moving up the focal lengths this becomes less so, and some variation of hyperfocal distance or mid-focus seems a better choice. And again, results will vary depending on the f/stop selected at each focal length. Also, after doing some "practical research" with my new Canon 17-40 f/4L lens, I found the "sweet spots" varied considerably from the Tamron 17-50 f/2.8; the f/4L could resolve sharper at higher f/stops than the Tamron could. So lens design and quality also figure into this equation. I can't go out and shoot the same way with my Canon f/4L as I do with my Tamron f/2.8 and expect the same results. I need to be aware of each lens's differences and shoot accordingly.

[Tom Maher]

I've been struggling with this myself. I look at timecatchers work and understand what they're doing but I can't seem to get that level of sharpness throughout the photo.

I'm currently using a K10D with the DA 16-45 lens and when attempting to take photos like the ones in this thread I can't seem to maintain an even sharpness across the photo. Of course I would like the foreground sharp but also maintain background sharpness. I was beginning to think it was the lens, and maybe still am.

[dbe4876]

Tom, there's no substitute for the following exercise taken with each lens you own/use:

Setup:
~ Find a landscape that has some good elements at various points throughout the focal distances (some objects of interest close, mid, and far).
~ Setup your camera and lens on a tripod, with cable release, and the camera set for mirror lockup and in single shot mode.
~ Set the lens to the shortest focal length (widest angle), put it in manual focus mode, and manually focus at infinity.
~ Put your camera in AV (aperture priority) mode, and set it to the largest aperture (f/4 on my Canon 17-40 f/4L).

Procedure:
~ Shoot at normal exposure and infinity focus across the major f/stops for the lens (e.g., f4, 5.6, 8, 11, 13, 16, 18, 20, 22), one shot at each f/stop (or, you can bracket if you like, letting the camera change shutter speed to keep the f/stop where you set it).
~ After you've gone through all the major f/stops for the lens at the first focal length, move the lens to the next major focal length and repeat the above process. Do this for each major focal length the lens has (obviously, I'm assuming a zoom lens here).
~ Now, repeat the process for all focal lengths on the lens where you manually focus to midway into the scene ("midway" is the next best alternative to "infinity" suggested by Harold Merklinger, see "Harold Merklinger on Depth of Field" Part IV, page 3).

Post processing,
~ Examine your images shot at various f/stops for each focal length, first for infinity focus and then for midway focus. You will be able to identify which f/stop is best at each focal length and which focusing method gave the best results. You can take this information and build yourself a grid in a little spiral notepad, to note for a given lens and focal length which focusing method to use and at which f/stop. This notebook goes into the camera bag and is a handy reference when you're out shooting.

Yes, it's time-consuming and pretty dern analytical. But once you've done this for each lens you will know more about that lens and how to best shoot with it than folks who have been shooting for years, guessing each time they go out and getting mixed results and never knowing why. In today's age of digital photography where there's no cost associated with taking lots of images, what have you got to loose?