[Wheatfield]

Ah, but sometimes it's an unwanted effect. One quality of waterfall photos is the juxtaposition of the hard and the soft, the sharp and the misty -- contradictory images in one. Diffraction diminishes that contradiction, softens the entire scene. Of course, stopping down all the way doesn't hurt if the picture is for a postcard.

It also doesn't hurt if there is no noticable loss from diffraction, which is often the case when taking photographs of things that are not 1000:1 TOC test charts.
The whole diffraction limit thing is mostly a myth brought on by people who pixel peep focus charts. In the real world of photography it is just one other thing that may or may not be something to consider.
If a very long shutter speed is called for, then a small aperture or a combination of smallish aperture and ND filter is also called for. If the photographer doesn't have an ND filter, then stop the lens down.

[RioRico]

Diffraction diminishes that contradiction, softens the entire scene. Of course, stopping down all the way doesn't hurt if the picture is for a postcard.

It also doesn't hurt if there is no noticable loss from diffraction, which is often the case when taking photographs of things that are not 1000:1 TOC test charts.
The whole diffraction limit thing is mostly a myth brought on by people who pixel peep focus charts.

And, without restarting the Diffraction Limit Wars, I must beg to differ. I refer to old handbooks on field and nature photography, written in pre-digital days by technical photographers concerned with maximizing IQ, and they emphasize the problems of diffraction, sometimes serious. I look at my own photos, where I may shoot wide and crop (a habit from my MF days), and see diffraction softening. I'm not shooting focus charts, and I'm not pixel-peeping -- there are times when I just need to squeeze out the best resolution possible.

No, diffraction is not a problem with small displays, small prints, especially matted-glassed-framed prints hung on a wall. Diffraction is also less of a problem in color images lacking sharp details, than in greyscale images WITH sharp details. In high-ISO noisy/grainy human-interest shots, diffraction is not a problem. But as I've pointed out, when we look at landscapes and flowers and arthropods, and structures and artifacts and such things, we want to see detail. And unless we display that image small, diffraction loses some detail.

In the real world of photography it is just one other thing that may or may not be something to consider.

Photography encompasses many real worlds. Let's look at a subset: group portraits. With a small informal group like a couple or family or some friends, a soft image may be desirable. With a larger formal group, a class or company or association, extreme detail is required, so individual faces may be more clearly discerned. Shooting that large group without attention to detail renders them faceless, which can be a provacative social commentary but won't be appreciated much if the group is paying for the shot.

But, back to waterfalls. Look above at the pictures by Tuner571 and especially shadeless. Their drama comes from the contradiction of the soft flow of water against the sharp detail the the surroundings. If printed postcard-size (even big postcards) diffraction would not be an issue. But shown any larger, they'd gain impact by the rocks and trees in one, and the icy edges in the other, being razor-sharp. Or Mike Cash's strobe-lit splashes -- if each droplet was an indistinct blur, why bother viewing? (And actually they do look blurred, which lessens the impact.) If a human was tumbling or surfing down the waterfall we could ignore the lack of definition. WOW! LOOK AT THE ACTION! But unless the intent is an overall soft impressionistic watercolor-and-ink suggestion of natural beauty, we'd rather see detail.

So much is dependent on the presentation. I've shot moderately long exposures of silkily-flowing-water-on-sharp-rocks in B&W with a 1mpx (912x1216) P&S, the image saved as a TIFF, rescaled and sharpened a little in PP and printed at 9x12cm, matted-glassed-framed-hung, that look great. Almost anything looks good if you keep it small enough. Even me. I hope.

[Tuner571]

It also doesn't hurt if there is no noticable loss from diffraction, which is often the case when taking photographs of things that are not 1000:1 TOC test charts.
The whole diffraction limit thing is mostly a myth brought on by people who pixel peep focus charts. In the real world of photography it is just one other thing that may or may not be something to consider.
If a very long shutter speed is called for, then a small aperture or a combination of smallish aperture and ND filter is also called for. If the photographer doesn't have an ND filter, then stop the lens down.

I would disagree with you on that one, I have noticed that when I was first starting into photography that a really small aperture was effecting my picture quality. On my first time out to shoot waterfalls I was using my DA16-45mm lens stopped down all the way to f/22. As the sun set I slowly opened the aperture up and when I was finished shooting at the end of the day my aperture was at f/8. When I returned home later that evening I uploaded my shots so that I could start working on them.

When I was looking at them at 100% I could easily tell a sharpness difference between the shots taken at f/22 and f/8. Now, I am definitely no pixel peeper but just looking at the photos at 100% made a big difference. This is why I now try to shoot long exposures at a much lower aperture to prevent diffraction from ever taking place.

I also want to say that my camera was on a weighted tripod and I was activating the shutter with the 2 second delay. So there is no possible way that I induced camera shake into the photo as well.

[snostorm]

Hi Laurie,

I quoted shadeless' post to emphasize it, not to answer it.

Since you have a K20, I think you'd do well to try the multi-exposure mode on your K20. You don't need ND filters, can shoot long exposures, even in bright sunshine, but you do need a tripod. In multi-exposure, you can set any number of exposures from 2-5 (on the K-7 it's from 2-9), and you need to check the auto exposure compensation box.

Multi-exposure mode is in the Rec menu at the bottom of the first page. When exiting after setting the number of shots and exposure compensation, you need to press OK twice instead of just touching the shutter release.

You need to set the shutter/aperture/ISO combination for correct exposure for a single shot, and the total exposure time will be 2-5 times the shutter speed chosen (depending on how many exposures were chosen in multiexposure mode). The shutter times are cumulative, and the camera compensates to get correct exposure.

If you are in continuous shooting mode, you only need to press and hold for the number of exposures chosen. If in single shot mode, you need to actuate the shutter for each exposure in the series. The K20 will continue to take single exposures after the chosen # of shots has been taken.

Multi-exposure mode on the K20 will turn itself off automatically once the exposures are complete. You have to re-enter the Menu and re-choose # of shots to take another shot in this mode.

M-E mode is easier to use with the K-7. There's a "start shooting" selection at the top of the M-E menu screen, and you press OK to start the exposure sequence. After the chosen # of shots is complete, the camera stops shooting, and you're returned to the M-E menu. The # of shots is retained. You only need to press the OK button while "start shooting" is highlighted to take another M-E shot with the same parameters.

Try it, I think you'll like it.

Scott

instead of using nd filters and possibly degrading image quality, you can try the bulilt in multiexposure function of your k20.

tripod is a must, though in this kind of shots.

this, for example, was done with multiexposure and a k20:

[flippedgazelle]

It also doesn't hurt if there is no noticable loss from diffraction, which is often the case when taking photographs of things that are not 1000:1 TOC test charts.
The whole diffraction limit thing is mostly a myth brought on by people who pixel peep focus charts. In the real world of photography it is just one other thing that may or may not be something to consider.
If a very long shutter speed is called for, then a small aperture or a combination of smallish aperture and ND filter is also called for. If the photographer doesn't have an ND filter, then stop the lens down.

I think the term "myth" is a little strong, but I do agree that the concern about diffraction is often vastly overblown.

I posted a waterfall image on this forum last year, and received highly complimentary feedback, including a recommendation that I submit the photo to the PPG. It was shot using the kit lens at something like f/36, IIRC.

I frequently shoot macros @ 100-300mm w/Raynox DCR-150 diopter lens and an aperture of f/22 and smaller. Shots are decently sharp and also receive highly positive feedback.

Looking at lens tests done at photozone.de, it appears that diffraction often sets a lens' resolution back ~ 10% (although in some cases it gets very extreme). So, if a f/2.8 lens reached peak sharpness at f/5.6, diffraction at f/16 causes a resolution characteristic similar to the lens being wide open. A little bit of softness is a small price to pay for getting the shot.

[flippedgazelle]

When I was looking at them at 100% I could easily tell a sharpness difference between the shots taken at f/22 and f/8. Now, I am definitely no pixel peeper but just looking at the photos at 100% made a big difference.

Judicious use of USM or Smart Sharpen, or a plugin like Focus Magic can ameliorate this to a degree.

Of course, I don't disagree that avoiding diffraction is a bad thing; but to abandon a shot or to declare a shot is a failure due to diffraction is to set to sea in a failboat, IMO.

[Wheatfield]

Most lenses have a sweet spot as was pointed out by Tuner571.

Here's food for thought. Lenses aren't as sharp wide open as they are at their sweet spot, but would anyone say you shouldn't shoot at a wide aperture if you want to limit DOF?
Or if you need a faster shutter speed?
The reality is, shooting wide open and shooting at minimum aperture are often going to return similar resolutions.
Check Yoshihoko's lens testing site if you don't believe me.
Here's the link:
http://www.takinami.com/yoshihiko/photo/lens_test/procedure.html

The tripe about lenses turning images to much at small apertures is bunk, though I am willing to accept that some lenses suffer more than others.

The bottom line is you do what you need to do to secure the picture you envision. If that means stopping down to minimum aperture and taking a slight resolution hit to secure a long exposure time, or deep depth of field, then that's what you do.
If you think you can get away with it, then shoot wider open as well. It's not like as if it costs a lot.
You do it for the same reason for taking a very similar resolution hit when you shoot wide open (and often take a contrast and CA hit in the process) to secure a fast shutter speed or shallow DOF.

EDIT: Stop to consider also, when you are stacking ND filters onto the lens, how much of a resolution hit is that extra glass costing you?

---

Last edited by Wheatfield; 04-18-2010 at 11:02 PM.

[RioRico]

The acid test, is to test and see, maybe in twilight. Camera on tripod, remote enabled, mode set to P. Try changing the program line. Shoot with and without ND's. Focus on the water or in front of it. Twist the dial through all the P-mode exposure possibilities: wide open to shut down. Don't accept anyone's theorization or authority or opinion on diffraction, especially mine. Assuming you have five minutes to dedicate to making a good picture, do so.

If you have more time, try shooting in monochrome, with different filter-effect settings. See if the form and shape and flow become more compelling without the distraction of colours. That mill and waterfall can be an ideal workshop for testing all sorts of different approaches and techniques. Sure wish *I* had a waterfall around here. Nothing drips nearby since all the snow melted off my roof. Darn.

[clmonk]

Personally, I think this whole issue of "cotton candy" waterfalls is funny. We spend the big bucks to get the fastest lens we can, then go out and shoot at f22 at 30 seconds (or some such) in order to get a blurry shot! Why do we want blurry shots? Seems blurry is all in vogue for the last several years (at least with flowing water shots) but I much prefer a sharp shot ANY day. To each his/her own!

[Wheatfield]

Personally, I think this whole issue of "cotton candy" waterfalls is funny. We spend the big bucks to get the fastest lens we can, then go out and shoot at f22 at 30 seconds (or some such) in order to get a blurry shot! Why do we want blurry shots? Seems blurry is all in vogue for the last several years (at least with flowing water shots) but I much prefer a sharp shot ANY day. To each his/her own!

I think Rico answered your question a few posts back.

[stevebrot]

Wow! What a long thread. I will add my piece to the OP's original question. This is what I do with moving water (falls and rapids):

• 1-2 seconds for silky blur (some definition present)
• 10 seconds for total blur (cotton candy)
• 1/10-1/15 second to retain a sense of motion (very useful for rapids)

Any times shorter than this will look more like snapshots. Not bad, just not as cool. A few other points:

• Cloudy days are the best days, less contrast in the scene
• Early morning or evening is good too (less wind to blur foliage)
• Remember that the white water is...white. Don't meter off the falls. A hand-held meter can be very valuable here.
• Shoot RAW so that you can adjust white balance more easily in PP
• As noted above, ND filters can really be a help. I don't own any, but they are high on my want list.

Here is a link to a few of my "water" shots in case you are interested: LINK


Steve

(Decided to not comment on the diffraction issue )

[Nesster]

I did a primer once:


Left to right: 1/100, 1/30, 1/2 seconds exposure

[hcc]

Nesster,
Very nice comparative shot. Excellent illustration of the shutter speed on water fall photos.

Well done ...

[Naturenut]

You guys are so awesome. I wish I could have you by my side (or be by your sides) during every outing for guidance. Gosh. Thank you so much for the great information. I will keep shooting until I figure it all out! If I get something decent, I'll be sure and post it.

[stevebrot]

You guys are so awesome. I wish I could have you by my side (or be by your sides) during every outing for guidance. Gosh. Thank you so much for the great information. I will keep shooting until I figure it all out! If I get something decent, I'll be sure and post it.

You are so very welcome! Here is a link to the Flickr photostream of one of the better waterfall photogs I know of. You can check the photo properties for clues on how it was done. She has the reputation of doing pretty much anything to get the shot including standing waste deep in icy water to get just the right angle.

Flickr: Konejita's Photostream

In case you are wondering...Yes, we do live in the same part of the world. We are fortunate to have literally hundreds of waterfalls within an hour's drive.


Steve