Polarizing filter?

[Holaday]

Question for the photo pros. Do you use a polarizing filter when shooting beads and finished silver/glass jewelry? I am about to purchase one for my 24-105 Canon lens (B+W 77mm circular MRC filter for $157.66) and wonder if I really need this. I've managed to live without one so far, but my photos do need improving... especially the beads.

I use hot lights (tungsten) and am wondering how many of you are using an off camera speed light (I am looking at the Canon Speedlite 580EX II Flash for Canon EOS Digital SLR Cameras) an even pricier item I have never used and suspect would mean a steep learning curve to use correctly.

Thanks for any input.

[Mike Jordan]

I have used them but not very often. I usually use my polorizer when I'm taking pictures of wet foliage to hold down the sparkle of the water drops and bring out the colors.

The down side to a polorizer is they reduce the amount of light (although this can work when you are trying to use a slower shutter speed in bright light to show movement like of a stream or river) which if you are not using a tripod or some other support can cause fuzzy pictures.

I use a variety of lights and have everything from studio lights to hot and cold lights. But most of the time, when I'm taking quick shots of the glass stuff I do, I just use my 580ex II flash because it's quick and easy. I usually throw a Photoflex 12" Litedisc in front of it to help diffuse it more than the little plastic diffuser can do by itself. The 580 puts out a strong enough flash that I can use several layers of diffusers and still shoot at f13 to f18 for good depth of field. If I fuse something that is better than my usual stuff and want to take really good pictures of it, then I get out my light tent, studio lights and softboxes.

Besides the 580, the 480 or even some of the older Vivitar flashes would work as well. You don't get E-TTL or fully automatic flash with the older ones, but you can put your camera into manual and do everything just as well as you can the 580. And you can buy several of the older, manual flashes and have money left over for the cost of the 580. You can also buy inexpensive strobes that screw into a light socket that puts out about the same light as a flash and work real well for shooting small items like this.

Mike

[Holaday]

Mike,
Thanks for the quick reply. You are the BEST!

Too bad I am such an impulse buyer... already ordered the filter. I am hoping the loss of two stops doesn't make the exposures too long with the lens closed down for max DOF. I look at my bead photos and can see the dust on the surface of the glass and the marks on the background paper, but the bead itself never looks sharp. I can't figure out what the problem is.

The overall quality of the photography on this forum has improved hugely over the years... and some artists photos are simply amazing.

Perhaps I will pass on the speed light for now. I have years of experience working with three big (hot) studio lights, tents, and reflectors. Just thinking these might be the problem... not enough "snap".

I'll save your suggestion re: the LiteDisc for diffusion. Do you work with the speed light on or off the camera?

Thanks again.

[Mike Jordan]

Carol, you may be stopping down to much. While the lens you have is a decent lens, it's still not on par with primes or the L lenses. It does have it's sweet spot though, which is about f11 to f13 and about 65 to 75 mm. At least that was where mine was for the years I used it before I moved up to all L lenses. You want depth of field but with most beads and glass, you don't want to much depth of field. A slightly out of focus background will focus (no pun intended) the eyes on the beads because of the way our eyes work. You don't want the forefront to be out of focus though as that has the opposite effect. Another thing to try is go to manual focus and adjust the focus yourself. Or make sure only your center focus point is active and not any of the others. I don't know what camera you have, but if it has multiple focus points and all of them are active, the one that can see the best, will select the focus. That may be affecting your focus.

I've used my flash off camera but mostly I use it on camera and either angled up with the Litedisc held above it so the light bounces back down or with the Litedisc in front of it to add more diffusion. It's a bit awkward doing it that way since I'm usually shooting down on my glass from a step stool and I'm holding an already heavy 1DMKII with the flash on it in one hand and my Litedisc in the other. But for quick shots that are just going to be put on the web to share, I keep the flash on the camera.

Mike

[Holaday]

Mike,
Very interesting about closing down too far and missing the "sweet spot". I'll experiment with the f-stops you listed.

But now you have me even more confused since my lens is an "L" even though it is not a prime.

Canon EF 24-105mm f/4 L IS USM Lens for Canon EOS SLR Cameras

My camera is always on a tripod and I use a shutter release cable.

I've also used a Canon "Normal EF 50mm f2.5 compact Macro Autofocus Lens" and have the same issues. Perhaps I am missing its "sweet spot" as well.

So which is the "best" Canon lens for photographing beads in your opinion, and what would be its "sweet spot"?

Never had these issues with my old Nikon and lenses. Not that I want to go back to using film!

Thanks once more for your help.

[Mike Jordan]

Oops, my mistake, I am thinking of the 28-105, which I don't think they sell any more. It was a non-L lens, although a decent non-L. The fstop still goes for primes though. There have been some very extensive debates and testing done on some of the Canon forums over shooting digital smaller than f16 and how it can cause distortion... although the real debate is if the average person would even notice it.

If you are having the same problem with both lenses, then it sounds like you might have more than one focus point active or one of the points other than the center focus point. Try manual focus as well as check your focus points. I use the center group but will switch down to just the center one when I want to make sure that what I'm aiming at is what is in focus. When I'm shooting action or fast moving stuff, then I switch to a wider grouping.

Well, the best lens is subjective but in my opinion it's hard to beat a 24-70 2.8L or the 70-200 2.8L or 70-200 4.0L. In fact, to some, it seems the 70-200 4.0L is a tiny wee bit better than it's faster counterpart, the 2.8L. I've had both for years and I like the 4.0L because it's smaller and lighter but I like the 2.8L because it's faster and looks sexier and more professional when shooting around those with black lenses.

I use the 70-200 with a macro tube so I can focus in closer for small things. But most of my close up and still life stuff has been with the 24-70 2.8L. These are all tack sharp with good contrast across their whole zoom range and pretty much their whole fstop range. The rule of thumb with most zooms in the past was about 3/4th of the way. Not all the way extended and not all the way closed and staying between f8 and f16. That put the image down the middle of the glass, which is usually it's sweat spot. The edge of the lenses (lower quality types) usually caused distortion that could be seen as fuzzies and low contrast.

Most of my still life stuff has been of flowers and other plants and it was only after I got into glass fusing that I started taking pictures of glass. I'd done some metal and polished stone jewelry in the past, but not a lot of it so glass took some practice. If I sold my stuff I'd take more time with it, but I don't have the room any more to leave my stuff up all the time and it's too much work to make room, pull it all out, take the pictures and then put it all away again, just for showing on the forums. I've gotten lazy in my old age. And you are welcome, Carol.

Mike

[Alaska]

This bead is done without using a filter. Notice the reflection from the light tent on the right and the glare from the soft box toward the left. The setup uses three flash heads. One on each on the right/left and one soft box off axis in front slightly off to the left. Bead is 17.73 mm OD.




The revised setup uses one flash head with a diffusion sheet and a linear polarizing filter 8 inch square on the flash head (no soft box). The lens is using a CP filter adjusted to remove as much glare/reflections as possible. Image shot in RAW at F22. Estimated 600 WS at the flash head to over come filter factors. Bead is 20.83 mm OD.



The filtered image is significantly improved over the non filtered image. Not perfect but acceptable.

[Holaday]

Alaska,
Thank you for the info and the images. Wow! three flash heads and two filters.

The CP filter arrives tomorrow and I will soon know if it improves my photos. Considering the cost of it, I am hoping for miracles. At some point I might invest in a flash head..... hopefully won't need three of them.

What lens are you using? Mike's info re: each lens having a sweet spot for sharpness makes sense, and I will experiment with that. I just can't wrap my mind around the fact that dust on the surface of the bead is in focus, and the paper directly under the bead is in focus, but the bead itself appears soft.

thanks again for the input.

[Alaska]

One can use incandescent light and use a longer exposure time. With flash the 1/200 is nice bonus.

The lens is a Canon 100-400 mm EF - LIS with extension tubes. The setup uses a CP on the lens and a linear polarizing filter on the light source.

B&H has larger polarizing filters as one source. Used the filter material sold by Aflash Photonics as it is available by the foot for a reasonable cost. See below URL. The PF-006 was placed in front of the strobe.

http://www.polarization.com/polarshop/

[Alaska]

Originally Posted by Holaday

Alaska,
I just can't wrap my mind around the fact that dust on the surface of the bead is in focus, and the paper directly under the bead is in focus, but the bead itself appears soft.

As a thought, place some black paper or cloth behind the bead. Something like a foot behind and then shoot an image. Sometimes light wraps around the bead from the white background making the edges fuzzy. However, not sure if that is the issue or not, but it is worth a quick exposure to check.

[Mike Jordan]

I like black cloth over paper as cloth doesn't reflect light like paper does. Even black paper has a tendency to reflect some light because of the chemicals they put in most papers.

Carol, it could be how the light is striking the the dust and paper, causing them to stand out more than the bead. Or it could be that the dust and paper that you see in focus are on the same focus plane while the bead itself is just before or just after that plane, making it's focus look different. It's hard to say without seeing it though.

Nice bead shot, Alaska. They don't look like the same bead at all, but a big improvement.

Mike