Attn: John Lucas, and/or any other photographers......

[odie]

Howdy John.....

I believe it was you that gave me some advice on how to make clearer pics of my turnings. As you will recall, I had a "depth of field" problem......clearer front edge of the bowl, and blurred rear edge. I had been using a macro setting from my digital camera, and you suggested I forget the macro and move the camera further back......and cropping.

I've tried everything......and am still having problems with clarity. I've now added some extra lighting, and this helps the overall photo, but the depth of field problems persist.

Here's something I don't believe I originally told you.......The camera I'm using is an older Canon S-30, and it's only 3.2 megapixels. Now, I'm thinking this 3.2 megapixels could be a part of my problems, if I'm going to move the camera back and crop to bring the subject to size within the frame. Am I right, or wrong about that?

I'm now considering the possibility of just giving up on this camera and purchasing one of the newer digital cameras in the 7 or 8 megapixel range. The one I've been looking at is a Canon S5IS. This has a macro setting and manual focus capability.

Is it possible to get clear photos from a digital?.....or, should I scrap the digital camera alltogether, and think SLR? I really don't want to become a "photographer"......all I want is to get good shots of my lathe turnings without putting in much effort to learn all there is to know about cameras.

Any comments?

thanx

otis of cologne

This photo illustrates about the best photo I can get of my bowls with my current camera and methods......the far side of the rim is not in focus......it gets worse from here!

 

[Ken Grunke]

Otis,
If you can choose the aperture setting of the lens, use a higher number to get better depth of field. When a lens aperture is wide open, it's focus is in a very narrow range so the opposite holds true for the smallest aperture opening.

You are on the right track on backing up to get better depth of field, and a camera with better resolution will do better in that regard. It will hopefully have a better lens as well. But more megapixels isn't the end-all solution. I have the Canon G2, 4 megapixels--maybe you have the same dial as mine? If you have "P", "TV", "AV", and "M" on the function dial above "AUTO", set it on "AV" where you can select the lens aperture (opening) manually.

The higher number gives a smaller opening and more depth of field. But it needs a slower shutter speed to compensate. So you need brighter light, and/or a tripod if the shutter speed gets below around 1/100 of a sec. Check your shutter speed by flipping to "TV".
"M" is manual, where you can adjust the aperture and shutter speed independently without the built-in meter doing it's thing.

Also, my G2 has a manual focus button on the side, which is nice. If you have that, set the point of focus a bit nearer to the front than the back, since the depth of field broadens as the focus moves away from the camera.

 

[Bruce McElhaney]

DOF (depth of field)

I've was a pro photographer for many years, so I feel qualified to answer your question. Cameras with manual settings and focusing abilities are very helpful, but not entirely necessary for maximizing DOF. Without getting too technical about lenses and such I can tell you DOF or range of focus is an optical thing and has nothing to do with pixels or film. It's all about focal lengths, apertures and focal distances.

To increase (DOF) Depth of field, you'll need to stop down the lens. (using a higher aperture number) for example using f:16 instead of f:4 Normally that requires for manual settings ability of the camera. Stopping down usually requires either a higher ISO number, more light or slower shutter speed for keeping the correct exposure. This is where a tripod is very helpful.

Maximum DOF is also obtained when focusing about 1/3rd of the way in on your subject (bowl) instead of its front rim. A camera with Manual focus ability makes that much easier. SLR (single lens reflex) cameras make life a lot easier and are the best way to go IMO.

 

[Joe Greiner]

I'm not familiar with that camera, but Google is your friend. First hit from [canon s30 "depth of field"] was this one:
http://photography-on-the.net/forum/archive/index.php/t-42994.html

Manual control of the aperture is the best way to control DOF. Like Bruce implies, it's all optical formulas. I'll spare you the gory details. BTW, the f-number is more accurately expressed as a fraction, e.g. f/16 instead of f:16. All this means is that the hole is 1/16 times the focal length of the lens. For a 32mm lens, the aperture would be 2mm. Bigger denominator -> smaller aperture.

An SLR, film or digital, can provide immediate insight. But digital "film" is cheap enough to do lots of experiments. Even with real film, the byword in Hollywood is "Film is the cheapest thing we've got."

Joe

 

[waltben]

The other thing is to use a monochrome or neutral background without any texture. That way the piece you're photographing is the single focal point and won't get 'lost' with the rest. I prefer either a black sheet or gray photo backdrop paper, depending on the effect I want.

 

[john lucas]

Depth of Field on bowls and platters is a problem even with high end SLR's. The reason is you are simply asking for an awful lot of things to be in focus. You are doing the right thing by backing off and then cropping. As Bruce said focus about 1/3 of the way through the piece also helps.
If your satisfied with the sharpness of the front rim then a higher megapixel camera won't really help unless you back off further and crop more. Then the higher resolution will help.
Manual focus and manual aperture are the way to go. That way you have control of where you focus and you can choose the smallest f stop your camera has. One thing I've noticed on the point and shoot cameras is the manual focus sucks. It's very hard to be precise. That may be where the problem is. If you can hook the camera up to the TV or monitor it helps because you can look at a larger image to focus.
The only other thing you can do to get things that are large and flat in focus is to move the camera higher. The closer the film plane is to parallel to the area that needs to be in focus the better. In other words if you put the camera directly over the piece both rims will be in focus. So obviosly this isn't always an option but sometimes just moving the camera up a little more and shooting down will help. Of course this changes the overall look of the photo and the piece so may not be of any use in this situation but it's something to know.
The only other option is one I use in the studio. That is a Bellows attachment that has swings and tilts. I only have swings on my bellow but I can rotate it 90 degrees and in affect get what we call tilt. This allows me to shoot a platter and get both rims in focus with a small f stop by altering the relationship between the lens and the film plane. If you want to know more look up schiemflug (if I spelled it correctly)

 

[odie]

Thanks John and all.......your input is certainly appreciated.

Joe, that link is helping.......(I'm pretty much a dummy about computers......cameras aren't my only area of technical illiteracy!) I guess I'm one who knows what he likes, pursues those things with enthusiasm, and have strong urges to not be bothered by things that don't interest me.

I'm playing around with this camera again, this morning.......still supervising a couple of 8yr old boys, so I've got some time to experiment with it a little.

I guess it's true that I'm asking for miracle solutions to something that is a major problem, even for the experienced photographers. I think I can settle for a little less than perfection, but I'm pretty sure I can do better than what I've been doing.

Off.......to the world of the unknown!

otis of cologne

 

[odie]

Gentlemen........

I've been going over the galleries on this forum with a critical eye to the photography.......and, I'm seeing quiet a few photos of large rimmed bowls like mine.......all with varying degrees of the same DOF issues I'm experiencing. I've gone over these galleries many times before, and have admired many of the turnings you are doing, but I've been looking at your artwork, not the technicalities of the photography. (If I use my head a little on this, I'd realize this is probably the same way others view my photos, too!)

Anyway, what I'm seeing are the same issues I'm dealing with. Now, I'm assuming that few of you are doing your photography any different than I am.....a novice with a middle-of-the-road digital camera, and limited photographic skills, lighting......and desire.

I'm feeling a little better about my lack of perfection in this, and with a little tuning up of my techniques.....I just might get some photos that are, uh, just barely acceptable! Ha!

otis of cologne

 

[seafoam]

One thing you don't mention is what you want to do with your pictures. If you just want to put them online, 400px wide like the one above, then you can stand back and crop quite severely, since your camera will go to 2048 x 1536 which is 6x wider than what you want.

I find it difficult to focus on these cameras since the viewing screen resolution is so poor. Auto focus is usually my best bet, so like someone else suggested, try a plain background so you can be sure the camera is focusing on the bowl, not the background.

But I think the picture is very good. If anything, I would be trying to eliminate or reduce the glare spots.

 

[john lucas]

One suggestion on focus although it might take an assistant. If your camera has focus lock, which most do, then you can place a card in the scene at the 1/3 point. Probably a big white card with a black X on it. Let the autofocus lock on this. Use the focus lock which is usually just pushing the shutter button down part way. Now pull the card and and finish pushing the button down. We did this successfully in one of the classes I taught.

 

[Bruce McElhaney]

Odie, Having you entire bowl in sharp focus may not be as important as you might think it is. While it is important for the front of the bowl to be in sharp focus, it is less important for the rear of the bowl to be in sharp focus. A subtle focus shift from sharp in front to soft the the back can help give an illusion of three dimensional depth in a two dimensional photograph. In any case, it's important to separate the subject from its background in some manor, for example with lighting, color, contrast or focus shift. Keeping the background simplistic holds the eye's attention on the subject.

To my mind the problem with your posted photo is definitely its background, not the DOF issue. The background contains too much texture and competes with the bowl for the eye's attention. A plain background, one with less texture would work much better, IMO. Graduated tone backgrounds also work well as they can increase the illusion of depth while remaining unobtrusive.

 

[Charlie Knighton]

Graduated tone backgrounds also work well as they can increase the illusion of depth while remaining unobtrusive.

while my photos are still not commerical quality, and i have problems being consistent, the graduated tone backgrounds have made my photos acceptble with my cameras autofocus the camera has 5 megapixels with 4x digital zoom and 12x optical zoom

 

[Bob Hadley]

This question may sound a bit basic, but is your lens glass dirty with fingerprints or dust?

It could also be that your lens may not be very sharp to begin with.

Regarding MP ratings, since no one mentioned it, we all agree that the "low" 3.2 megapixel number is NOT a factor.

John Lucas: do you agree with that?

Also, point-and-shoot lenses vary quite a bit.

As the owner (between wife and I) of maybe 10 digital cameras, I attest to a wide variance. My favorites have been Fuji FinePix (F10/30) and Olympus. Our friend has a new Panasonic (a variation of the Leica) that is fantastic. As for Canon, Nikon and Sony, we’ve been disappointed (talking point-and-shoot, not DSLR).

FIY: I sill use an ancient 2.1 megapixel C-700 Olympus from years ago for web images. The lens is superb! It always blows people away that I use it sync’d to my even more ancient Norman P2000 powerpack and strobes! But the images are pretty much razor sharp. If you doubt it check out my photos in the forum:

http://www.aawforum.org/photopost/showgallery.php?cat=500&ppuser=218

 

[john lucas]

I would agree that the MP factor is not a factor with depth of field, unless you need to back off and crop the photo extensively. Then megapixels matter.
One problem with many of the point and shoot cameras is that they simply don't have small apertures. They may only go to f8 or f11 but this is a little misleading because f8 with a small CCD might give you the depth of field of F11 on a larger CCD.

 

[Bill Boehme]

FIY: I sill use an ancient 2.1 megapixel C-700 Olympus from years ago for web images. The lens is superb! It always blows people away that I use it sync’d to my even more ancient Norman P2000 powerpack and strobes! But the images are pretty much razor sharp.

Your pictures are very well done. However, I don't know if you noticed that your images have major dust bunnies on the sensor (those little gray dots that are about 1/8" to 3/16" diameter). Some photo software programs allow you to map out dust bunnies. The alternate solution is to have the sensor cleaned which may not be worth the cost for a P&S camera. Those cameras are not environmentally sealed and the zooming lens acts like a little bellows to pump dirty air into the camera body and onto the surface of the sensor. With digital SLR cameras, it is a fairly easy matter to clean the sensor since the lens can be removed to get to the sensor. It would be major surgery to do the same with a P&S camera.

 

[Bob Hadley]

Actually it is my background paper. It is sometimes filthy with tire tread marks and dirt from various (non-wood) product shots. What looks like sensor dust blurs are really sloppy clone-tool retouching in Photoshop on my part.

Sensor dust is annoying for sure. My Canon DSLR is like a dust magnet. Although the manual warns against it, my dealer cleans it with a kit that Canon sells in Japan to consumers for that purpose (I read about it in a great book on the Canon DSLRs by David Busch) . Seems the idea of ham-fisted Yankees damaging their sensors by failing to follow instructions (and thus creating warranty nightmares) was too much too risk.

BH

 

[Bill Boehme]

Actually it is my background paper. It is sometimes filthy with tire tread marks and dirt from various (non-wood) product shots. What looks like sensor dust blurs are really sloppy clone-tool retouching in Photoshop on my part.

Sensor dust is annoying for sure. My Canon DSLR is like a dust magnet. Although the manual warns against it, my dealer cleans it with a kit that Canon sells in Japan to consumers for that purpose (I read about it in a great book on the Canon DSLRs by David Busch) . Seems the idea of ham-fisted Yankees damaging their sensors by failing to follow instructions (and thus creating warranty nightmares) was too much too risk.

BH

Thanks for clearing that up.

I use SensorSwabs and Eclipse E2 fluid to clean the sensor on my Canon. About a year ago, our club had several days of classes with Stuart Batty and I was at a couple of the classes taking pictures. Unfortunately the telephoto lens that I used was one of the "trombone" types that was not environmentally sealed. I discovered about a week later that during all of my zooming with the lens in that extremely dusty environment that I had sucked in huge amounts of green wood dust. All that wet lignin along with various VOC's had glued lignin and cellulose blobs to the AA filter on the front of the sensor. It took about six cleanings before all of the crud had been removed. I presume that the interior of the lens is probably full of that stuff ... creating more flare and ghosting than it had before, but it is not a lens that I use any longer and it is not worth the cost of cleaning.

Bill

 

[john lucas]

I use the same sensor cleaners as Bill. We have 7 digital cameras at work and so far I haven't damaged any of the sensors. Just follow the instructions carefully. Of course on a P@S camera you can't do anything except retouch the spots later.