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sparkie1263
02-13-2008, 04:56 AM
What filters should I get? I know that I know I want a Circular Polarized Filter but are there any other filters that are a must have. I also started a post about thaking IR with my Sony A100 but nobody responded, So I don't know if that filter is even an option.
Thanks
Frank

DonSchap
02-13-2008, 06:12 AM
When it comes to filters ... digital is kind of nice because most filter activity can take place AFTER the image is taken ... especially color enhancement or correction. That eliminates a sizeable number that used to kind of be "required" when using a film camera. especially with black & white film.

Basically, the polarizer is your biggest factor, because that cannot be corrected for, afterwards, without some major clean-up and pasting. It usually eliminates or reduces glare & reflections. It deepens the color of the sky, as you adjust for stray light and can enhance most images that deal with direct sunlight.

Also take into account that on an f/6.3, f/5.6 or even an f/4 lens using a 1.4x or 2x teleconverter ... it can interfer with Autofocus performance, because the polarizer chops down the available light to the sensor from f/0.7 to f/1.4 worth of light.

A Neutral Density filter can also be a boon to a photographer, as it cuts down the light in high contrast situations. Say you are taking a building against a bright sky ... the lighting situation will silohuette the building. But, using the ND-filter reduces the available light by a set amount and will allow you to recover the building with or an increased exposure. It also allows you to use a w-i-d-e-r aperture with it, to get more bokeh-effect out of an f/2.8 aperture lens.

They come in several densities ... and also graduated. Look into them (nop pun intended), online.

Most other types of filter are for special effects.

Hope this helps.

sparkie1263
02-13-2008, 06:20 AM
Don I will look into the ND filters. How come you never responded to the IR filter. I want to try this. I can't get an answer to this on any site. Is that something you can do with PS also.
Thanks
Frank

DonSchap
02-13-2008, 10:25 AM
IR is something the camera has to be able to do, naturally.

It is my understanding, through discussions a couple of years ago, that there is an IR-filter over the camera's digtial sensor to prevent Infra-Red light from distorting the image detected, therefore Infra-Red would be impossible to do without its removal.

Film, obviously, does not do this. In fact, there is IR-film specifically designed to enhance this end of the spectrum requiring use of IR-filters to filter out normal light. If you were to place one of these IR-filters on a digital ... you would effectively get ... well, no light at all. :eek:

If I am wrong about this, I apologize ... but since you've pressed for an answer .. there it is. It wasn't something my interests revolved around ... although I did sleep at a Holiday Inn Express, last night ... (sorry, wrong commercial) ... I did get a rather neat image, a couple years ago ... using Photoshop to alter the spectrum just a wee-bit ... kind of making it look Infra-Red. I mean, look at those trees off in the distance ... or that strange sky. This was inversion theorapy ... for photographers. It allowed me to realize you could do some significantly interesting things with B&W.

33199
@ Oakton Community College, Des Plaines, IL

sparkie1263
02-13-2008, 11:08 AM
Very nice picture Don. Was that done in PS? I am just looking for new things to try. The trees don't have leaves here yet so I have some time to look into this. From what I heard you cannot get the IR effect from pine trees.
Thanks
Frank

Don I just found this site and somebody posted som IR pictures they took with the a100 and a IR filter. What do you think?

http://www.thephotoforum.com/forum/showthread.php?p=1121467

DonSchap
02-13-2008, 03:02 PM
Like I said, Frank ... forgive me if I'm wrong about this. IR work with a digital was a discussion memebers of the DCRP had before the A100 was ever released ... so if it can do it, go for it.

I just don't have any information on it. I can ask at the photo lab, tonight, to see if any of the other college folks have any experience with it.

Aside from that, I am getting a microscope adapter (http://www.microscope-depot.com/digadapt.asp) ... for my Biology class. I'm just too lazy to draw the damn image view by hand and with thousand$ already invested in my photography ... it seemed a small price to pay to expand my range.

Or rather than expanding ... should I say:

SHRINK ?

There are photographic microscopics, that have a third ocular tube for the camera range in price from $600 to $1100

33204 And the one's with the camera built in 33206
where the price goes to $1300

or how about where the oculars disappear and the entire head of the microscope is an LCD display! Prices range are easily $1600, depending on the quality and the size of the image you choose. Most of the camera-types have USB output to your laptop.

332013320233203

Since the school has already foot the bill for the flippin' microscope ... I chose just the adapter, rigged up kind of like this.

33205

I'll get a better (real) image of this attachment after the adapter arrives. It should be a cool experiment in photography, all by itself.

Now, there's some exciting photography, eh? Ameobas and bacteria! :eek:

sparkie1263
02-13-2008, 04:40 PM
I did not doubting your answer I was just looking to see if it could be done. I want to see some of the pictures you take with that.
Thank
Frank

DonSchap
02-13-2008, 06:42 PM
Okay ... went down to the photography department, at the college, and inquired about IR-Digital. As I was correct in my first recollection ... digital cameras initially were prevented from using the IR-spectrum. The α100 departed from this norm ... and effectively is one of the first to do it.

It really is not HEAT photography, but basic enhanced red-photography. More passive than active ... you cannot see heat traces or things of that nature, but a deeper red-shift in colors than is humanly possible. I was told this is an effect, rather than a forced method.

SO, with that said ... the infra-red filter you would place on your lens will block most visible light and allow the camera to enhance slightly the long-waved spectrum underneath it. Call it "Enhanced-Red" to be more honest. :cool: It normally requires a much longer exposure for definition than normal photography, so a tripod will be essential.

Here's a link (http://www.dimagemaker.com/article.php?articleID=773) to some further discussion on this novel photographic technique.

Good luck! :D

sparkie1263
02-14-2008, 04:54 AM
Don you are the man. I just put that filter on my birthday list. So I when I get it I will try it and post my results. That microscope setup looks neat. I am glad it is something I am not into. I would not want to foot the bill for that setup. Good luck and I can't wait to see the pictures.
Thanks
Frank