Tag Archives: D70

Q&A: Which Body to Buy?

(This post is from an email conversation with a friend of mine who was buying his first DSLR. I thought the content might be useful for others.)

Q:  My question is whether I should rather go for the D40 and spend more $$ on lenses?

I am just not sure whether the D5000 would be a lot simpler for a novice like me.

A:  I didn’t realize that the price of the D90 had come down. It’s now at $810. So it should be in the running, too.

With respect to the D40, it’s a very good camera. The pros are that it is small, cheap, and light. It also offers 1/500 sec. flash sync, which is really useful for fill lighting in daylight. But it is a three year old camera. (I didn’t even know they were still selling new, as I was looking to pick one up six months ago and they weren’t available. There are two main down sides. Most importantly, the sensor uses older technology and will not be good in low light. Above 640 ISO or so, the pictures will be noticeably noisy, so you will need a flash indoors. And second, it will only work with AFS lenses, the lenses that have the AF motor built in. That’s OK for the 18-200 (and every lens that I regularly use), but there are lots of lenses out there (like most of the cheaper non-zoom fast lenses, e.g., all of the 50mm lenses except the new $460 AF-S version) that will not autofocus with it. So that’s a consideration.

Here are some pictures that I took with my D70, which is a 6MP camera that probably has the same or at least a similar sensor to the one in the D40:

Angkor Wat

Bayon Temple

Ta Prohm

Trenna and Ashlynne

Flower

Cambodian Girl

Green Heron Siblings

(If you get really bored sometime, here’s my photography site.)

The D5000 has the same AF-S requirement that the D40 has. But it is small and light, and uses a very good recent vintage sensor (12MP), so it will be good to at least 1600 ISO, probably negating the urgent need for a flash.

The reason I would consider the D90 is because it costs just a little more than the D5000, and it is a better camera than the D5000 in most respects. The only thing you lose is that it is bigger. But it also has a good recent sensor (12MP) and will work with all lenses.

I realize I haven’t made the decision any easier.

Overriding principles to keep in mind:  The lenses are more important than the body. The photographer is more important than the equipment.

Case in point:  We had an event a month ago up in Colonial Williamsburg, VA, where we had some photographers go out in the AM to shoot and then gave them hands-on with our pro photography application, Aperture, that afternoon. The best picture of the day was one taken by a guy using a D1H, which is an old 4MP made in 2001! It was an incredible shot, due not to the body or lens, but the photographer.

Any of the three bodies will take great pictures. If I had $1k to spend, there’s no question that I would buy a D40 and 18-200 used and know I could take great pictures in most settings. You’ll be replacing bodies from now on, but the lenses you buy now will stick with you for decades.

Hope somewhere in there is some helpful info.

Postscript:  He bought the D90 and a used 18-200. We’ll see how it turns out!

[Update, 6/30/15 – This post is moved from my old web site and thus all of the links are broken.  I’ll update them as soon as the rest of the site is finished.]

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Using a Polarizer to Increase Color Saturation

Typically most discussions surrounding the use of polarizing filters center on how they are used to eliminate reflections.  Another less often mentioned benefit (actually just an implication of removing the reflections) is increased color saturation.

While setting up for a waterfall shot, I noticed people walking underneath and tried to grab a quick shot to show scale. I hadn’t yet finished composing or setting the polarizer. The left-hand shot shows how the scene looked w/o a polarizer (it was on the lens, but not rotated to the correct angle to get any benefit). Reflections are evident on the leaves and on the rocks at the top and bottom of the falls.

The right-hand image from less than a minute later is the same scene (zoomed in a little) and same exposure with the polarizer adjusted for maximum effect. The most obvious difference is on the foliage, where the removal of the reflected sky really brings out the color, and thus increases the color saturation in the image. Less obvious, but still helpful, is the removal of reflections from the rocks and water at the top and bottom of the falls.

Polarizer set for maximum effect

Polarizer set for maximum effect

Polarizer set incorrectly

Polarizer set incorrectly

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Only post-processing was matching the color balance on the waterfall. Identical exposures (except zoom setting).)

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Infrared Photography with a DSLR

Angkor Wat from Phnom Bakeng (IR)

Angkor Wat from Phnom Bakeng (IR)

Plate 1

One of the neat features of the Nikon D70 is that it is probably one of the last DSLRs that can be feasibly used for infrared photography. Digital sensors are very sensitive to IR, but the designers put filters over the sensor to prevent that invisible light from messing up the image. As manufacturers introduce new models, the “hot filters” are getting better and better at blocking IR from the sensor.

BTW, when we talk about infrared photography, we’re really talking about near infrared.  Normal sensors are not able to image heat or see in the dark without artificial IR illumination. Visible light ranges from violet (around 400nm wavelength) to red (around 700nm). Mainstream infrared film (and digital) is sensitive up to 900nm or 1000nm. Radiation from heat doesn’t start until around 3000nm.

When you shoot IR, you are focusing (sorry) on the wavelengths of light from around 700 to 1000nm so you filter out the visible light with an IR filter. IR filters appear completely opaque to the eye, making direct composition impossible with an unmodified DSLR.

I’ve shot with the most popular black and white infrared film (now discontinued), Kodak High Speed Infrared (HIE), and really liked the unique characteristics of that film. The two major characteristics (besides its IR sensitivity) were its lack of antihalation backing and its very pronounced grain. The missing antihalation layer meant that the light from a highlight area of a scene could go through the film, reflect off the camera’s pressure plate, and add additional diffused exposure to the emulsion, causing the highlights to glow.

HIE was pretty difficult to use. It required special handling in your camera and darkroom, and the results could not easily be predicted, since you were dealing with invisible light and had no feedback.

Well, you can mimic the look of the HIE process in digital with less effort and instant feedback. There are lots of web references by people who are doing this with many unique processes and helpful pointers. I’ll discuss here the steps I took with the IR shots in my Angkor Wat Infrared gallery and use the photo “Angkor Wat from Phnom Bakeng” as my example.

2006-01-26-17-47-54

Plate 2 is the view in visible light right before the IR shot. The sun had already set and the sky was completely overcast. In addition there was a pretty heavy haze. Compare with Plate 3 below to see the absence of haze on the IR shot.

2006-01-26-17-42-10

Plate 3 is the unedited photo in IR. Note the required exposure increase. (1/125s @ 2.8 vs. 20s @ 5.6.) That’s about a 9.5 stop increase, and is pretty typical with the D70. Of course, in the daytime with an ISO bump to 800 it is still marginally hand-holdable, but this post-sunset shot required a tripod (actually a rock…).

Getting Started:

To shoot IR, you’ll need a camera with some IR sensitivity, a filter, and probably a tripod. You can check the web to find out about your camera’s usefulness before you invest in a filter.

There are a number of filter options. As you go from red to infrared, you’ll find the following Wratten filter numbers:  25, 29, 70, 89B, 87, 87C, 87B, 87A. I use the Hoya R72, which is equivalent to the Wratten 89B. The R72 filter is the first in that sequence that is visually opaque, but it still transmits a significant amount of red light. That’s why the unprocessed shots are red. Stronger IR filters reportedly produce nearly monochromatic images and give a stronger IR effect, but they also require more exposure.

Since I bought the filter to fit on my primary lenses I used back when I shot 35mm film, I have to use a step-down ring to use the 62mm filter on my 18-70. At its widest setting there is serious vignetting. Not a great idea, and very tough to hide. It’s useless on my 12-24. I used my 180/2.8 for this example and I had to hand-hold the filter on the end of the lens since it’s way smaller than the 180’s 72mm ring and I don’t even have a step-down for it. The filters are very expensive, so get the largest one you will ever need and then buy step-up rings for your other lenses.

A tripod is really necessary for IR photography, but this particular shot is the only IR photo I took in Cambodia that wasn’t handheld. Bad practice, but I took multiple shots of each to have a better probability of getting one sharp.

When you’re shooting a DSLR, you are shooting blind just like with film, so that’s another reason to use a tripod. You can frame with the filter off, and then add the filter for the IR shot. If you shoot hand-held it’s a guessing game and you end up making a lot of exposures before you get one that is framed right, aligned with the horizon, and sharp.

Shooting Tips:

Shoot at a relatively small aperture. IR light focuses on a different plane than visible light (with most lenses).  (See the cocam link for a visual illustration.) In the old days lenses had IR marks on the focusing ring to tell you how much to offset your focus. Few do today. Since I’m shooting blind anyway I let the AF focus with the filter on and shoot at a smaller aperture to get greater depth of field, in case the AF accuracy is lower in IR. I haven’t tested it, but logically it seems like the AF should work fine with the filter in place. Until you test yours, stop down.

Get plenty of exposure. On the D70 with the R72 filter, most of the exposure is on the red channel (as evidenced by Plate 3). Since I usually get most of my data from the green channel for the B&W image, I want to get enough exposure in that channel for a usable image. You may need to overexpose by a stop or two.

Block the light coming in the viewfinder. I usually have the camera set on auto exposure, aperture priority. Unless you set the exposure manually, you will definitely need to cover your eyepiece for the exposure. Otherwise the relatively bright unfiltered light coming in through the viewfinder will make the meter underexpose the heavily filtered light coming through the lens. (It can make a three stop difference or more on my camera.) Better cameras have an eyepiece blind for this situation. I use my thumb on the D70. If you are using manual exposure, this won’t be an issue.

Consider using a faster ISO setting. I usually set the D70 to ISO 800 for IR. One of the characteristics of the old HIE film was its very noticeable grain. On my D70 the noise caused by the higher ISO, longer exposure, and frequent underexposure of the green and blue channels looks a lot like the grain of the film. Alternatively, this can be simulated in post-processing.

Try white balancing with the filter on. After returning from Cambodia, I read about someone who does a custom white balance with the IR filter on the lens. I’m eager to try that, as it would make the initial images much more neutral in color. It would probably also make any overexposure bias unnecessary to get adequate exposure on the green channel.

Choosing a Subject:

You never know what will be a good subject. Certainly most scenes with foliage are potential subjects. Blue skies with some puffy or wispy clouds can really add drama. The haze-cutting ability of IR will often add depth to landscapes with distant vistas. And don’t shy away from portraits either. The best advice is just to shoot a lot of pictures and learn what catches your eye and produces the look you want.

Post-Processing:

1. The first step for post-processing an IR shot is to balance out the three channels with an auto-level in Aperture or Photoshop (Image > Adjustments > Auto Levels). In our example, Plate 4 is the result. (Compare Plates 2 and 4 to see the dramatic reduction in the haze.) (Note also that this step would probably be unnecessary if you do an auto white balance before taking the picture.)

2006-01-26-17-42-10 (2)

Plate 4

I do the remaining steps in PS. I’m using PS CS2 in this example.

2. Convert the image to B&W. I use the Image > Adjustments > Channel Mixer to both convert to monochrome and strip out the channels I don’t want. First I select the monochrome check box. Then I use the sliders to obtain the desired effect.

On the D70 with R72, usually the red channel is the softest and has the least noise. The blue channel has by far the most noise, but can offer darker skies and water. The green channel is usually the sharpest with moderate noise.

Each image varies, but a starting point is 100% Green, maybe 25-30% Red, 0% Blue, and a “Constant” adjustment of -20 or so to get the brightness right.

Make sure that you keep any highlight tones where you wish to keep detail in the final image a little darker than usual since the last step will blow out the brightest highlights.

3. Take care of spots, tonal range, and any other retouching if needed. Often I’ll use Image > Adjustments > Shadow/Highlight to bring up detail in the shadows and get detail back in the highlights at this point.

4. Sharpen the image. I use Filter > Sharpen > Unsharp Mask to sharpen the image at this step of the process.

Depending on your preferences, you might want to stop here. I like the look of HIE, so I continue with one last effect to mimic its glow.

5. Convert down the image from RGB/16 to Gray/8. Image > Mode > Grayscale, then Image > Mode > 8 bits/channel. Necessary because the final filter step only supports 8 bit depth.

6. Use the Diffuse Glow filter. Filter > Distort > Diffuse Glow. You don’t need much. I already have the grain, so I leave Graininess at 0. As a starting point I try Glow Amount 2 and Clear Amount at 17. I can’t describe exactly what each one does, but you’ll see it as you play with the sliders.

The result is Plate 1 at the top of the post. It’s fun to play with and sometimes the results are very nice. And it is definitely much easier than the old film method using HIE.

Other Ideas:

For those who do not have a suitable camera or filter, or just don’t want to shoot blind, there are options. Of course, one option is to buy an older camera like the Nikon Coolpix 9xx and a filter for it. Since point and shoot cameras typically have a live LCD viewfinder, you can see the scene just like with visible light.

Check out http://www.nickgallery.com/web_pages/technical%2020.htm for a simulated IR effect PS process that doesn’t require any filters or special camera techniques. I don’t expect that you would get the same haze-cutting ability as true IR, but otherwise it might produce similar results.

If you get really excited about IR photography, then there’s really only one thing you can do. Convert your DSLR to an IR-only camera! A number of sites on the web discuss how to remove the hot filter from your sensor and replace it with an IR-pass filter. Or there are others who will do it for you or sell you a camera with it already done. That gives you a dedicated-use IR camera that needs no filter, is sensitive enough to IR to allow normal exposure settings, and retains the use of the viewfinder for composition.

Links:

You can find many web sites discussing digital IR photography.  Here are a few good ones I’ve found:

http://www.naturfotograf.com/UV_IR_rev00.html#top_page – Bjorn Rorslett’s excellent site

http://www.wrotniak.net/photo/infrared/- just about every aspect of IR photography

http://www.cocam.co.uk/CoCamWS/Infrared/INFRARED.HTM – another good IR site

http://www.nature-photography-central.com/infrared_photoshop_tutorial.html – IR post in PS

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