Monthly Archives: July 2011

Tutorial #8: Calculating Hyperfocal Distance

Shooting at your camera’s Hyperfocal Distance will allow you to capturing the maximum depth of field possible for any given aperture. This is most useful for shooting landscapes or any scene where you want as much of the foreground and background in focus as possible in one shot. For every camera film or sensor size and aperture combination, there is a distance at which you must focus your lens on to achieve this maximum depth of field. It is the closest distance at which you can focus while still keeping objects at infinity appearing to be in acceptable focus.
 
:( The Math Stuff:
 
Of course there are all sorts of calculators and apps that will do the math for you, but in case you’re ever stuck in a position where that kind of tech isn’t available it’s always good to know how to do it yourself – even for someone who hates math as much as I do…
 
The formula is fairly simple:
 


Let’s use the example of shooting at a focal length of 17mm with an aperture/f-stop of f/8 on a Canon with an APS-C sized sensor. Take the focal length and multiply it by itself [square it] then divide it by the product of the f-stop number and the circle of confusion number and add the number of the focal length. The circle of confusion depends of the cameras sensor size The chart above contains the most common sensor types, but with a bit of research you can find the circle of confusion for even point and shoots and phone cameras. The result that you get will be in millimeters so you will need to convert that to something that is usable such as meters or feet. Just move the decimal 3 spaces to the left and round it off. You will get about 2 meters as your hyperfocal distance.That’s about 6 1/2 ft.

((17 x 17) /( 8 x 0.018)) + 17 = 2023.94mm = 2.02m = 6.63ft

Shooting Tip 01:
Some lenses have markers for showing focus distance (many Sigmas lenses). However, these markings can become unreliable under different temperature conditions that can cause the parts of the lens to expand and contract. A quick trick you can use is to either measure (if you want to be very precise…) or make an educated guess of the hyperfocal distance you’ve calculated and find an object to auto focus on at that same distance. Once focused, switch the lens to manual focus to lock it.

Shooting Tip 02:
Keep in mind that shorter focal lengths and smaller apertures increase depth of field so using these can get you shots that appear in focus from close in the foreground all the way to the farthest parts of the background.

The Results:

Notice how the stuff up close is just as sharp as the stuff furthest in the back.





…mainly religious imagery not intentional lol…I just found these to be the best examples because the statues are close in the foreground…and I’ve shot quite a lot of local landmarks for work…i guess there are not really many non-religious statues around here now that I think of it…

Tutorial #7: Macro Photography for Under $10

Macro lenses are expensive, so good thing there are cheaper ways to do macro photography. I’ll go over Reverse Lens Mounting and a bit on using extension tubes.
 
Supplies: First, I’ll go over the things you will need and some you might want to have…
  
01. A tripod (optional)

02. An SLR camera with a kit lens or any lens 50mm or wider.


 
03. A reverse mount ring (optional but recommended)

 
04. AND/OR An extension tube


 
Shooting Tip 01: Aperture Size & Depth of Field
The results will have a very shallow depth of field, so you will need a small aperture to increase the depth of field enough to have a decent amount of the image in focus rather than just a couple of millimeters. You will want to set the aperture to f/11 or f/16. You might not be able to see much when composing the shot if there isn’t a lot of ambient light, but it can mean the difference between this:
 

 
and this:
 

 
Shooting Tip 02: Manual Aperture Hack
If you’re shooting Canon and the lens you’re using doesn’t allow manual aperture control there is a “depth of field preview” button right underneath the lens release button. This button temporarily sets the aperture so that you can preview the depth of field by closing up the aperture to the setting of your choosing. Normally, the aperture is set to the max aperture [wide open]. I don’t really see the difference in its intended use, but it has a much more useful purpose.
 

 
Just set the aperture in the camera’s settings and press the DOF button while removing the lens. It will hold the aperture setting once removed.
 
Shooting Tip 03: Lighting
The lack of light from using a very small aperture will likely cause you to need more light and even a higher ISO to avoid camera shake. A flash can come in handy. Sometimes, you can get away with using a built in flash if you can figure out how to bounce the light just right, but you will probably need an external flash or some other light source. It could even be something you already have lying around like a desk lamp…
 
Shooting Tip 04: Focal Length & Magnification 
The wider the angle (the shorter the focal length) the more magnification you will get. My favorite focal length to use when shooting bugs is 35mm. Using an ultra wide lens will produce some extreme macro shots like the ones i posted below taken with the 10-22mm lens.
 
The Camel Logo on a Cigarette
Camel
 
Eye Shadow

 
 Shooting Tip 05: Focusing 
You will need to manual focus each shot. It helps to physically move the lens [and yourself] back and forth to focus once you have the focal length and the focus set. Once you try it out you’ll get a feel for the limitation of how it the lens is able to focus. You will need to be so close you are nearly touching the subject – especially with shorter focal lengths [18mm] 

 

Method 01: Free-lensing
Reverse Free-lensing is probably the cheapest method. It’s possible to do it with just the kit lens, and no extra attachments need to be purchased. In this method all you do is hold your kit lens reversed in front of your lens-less camera. You will also get a tilt-shift effect depending on how you hold the lens. There are a few drawback such as, dust getting into the camera and lens and light leaks. Here is a photo I took with a 10-22mm wide angle lens of my hair. You can clearly see my terrible split ends. :-/



Method 02: Using a Reverse Mount Ring
A Reverse Mount Ring can be purchases anywhere online for anywhere between $4 & $8. It’s probably best to purchase a common size like a 58mm ring and just get step up or step down rings for any other lens sizes. To use it, just attach the ring to the filter end of the lens and then attach to the camera. I find this to be the best way to get good macro shots. I don’t have to worry about light leaks or dropping the lens. Dust (and other things) can still enter the open end of the lens. I once had a jumping spider jump right into the lens! D:

I eventually got the spider out… This guy, actually:



Method 03: Extension Tube
Using a 50mm lens and an extension tube can give you similar results to reverse mounting, but extension tubes can cost $10 or more. It simply attaches between the lens and the camera to increase the focal length, but it doesn’t do much to increase working distance. You still need to get extremely close to focus on a subject.

Method 04: Combination
You can go on to combine the extension tube and a reverse mount ring to get even more magnification, but it still wont increase working distance and the depth of field may become too shallow. But of course, you can experiment with that if you like…
The Results:
I find that my best shots were taken with the reverse mount ring method.




I even shot some stereoscopic 3D macro shots, so you can get pretty creative with this stuff. [Cross your eyes until you see the 3D effect]



and to give you a better idea of the scale of some of these things…


If you want to see more examples, check out the Flickr Set with all my Reverse Mount Macro Shots.
http://www.flickr.com/photos/life-in-edit/sets/72157627268955398/with/5753211296/

Sure, a real macro lens will give you some good working distance, but the point here is really to have fun doing macro photography for under $10. You get what you pay for, sort of…

Tutorial #6: HDR Photography

High Dynamic Range Photography is fairly easy to do with a tripod and some HDR software and an image editing program. I’ll go over several ways to do it.

Dynamic range simply means the range of values between lightest and darkest visible tones. The idea behind HDR Photography is similar to the Zone System. I think of it as an extension to the Zone System and one of the modern applications of it in digital photography. It’s not just about making cool almost surreal photos, the goal is to capture tones in every zone. For more info on zones and tonal values see my previous post: [Tutorial #5: The Zone System]
 
For this tutorial, I’ll be using both Photomatix to quickly create HDR images and Photoshop to create them manually. First I’ll go over Photomatix. It’s reasonably priced at $99 for the pro version and $39 for the light version. http://www.hdrsoft.com/ Anyone can use the trial version which never expires but does watermark images made with some of the advanced features.
Photoshop CS5’s new feature is not very good…it really REQUIRES raw files for actual HDR images…and just gave me an error message about my images not being the same size…so converting to JPG or shooting in JPG will result in a terrible image.


no, not ok, adobe. :<
It once even rendered a completely black image. Not very HIGH in dynamic range at all. :-/

Step 01: Shooting
 
If you want to do HDR the right way, you will need to Bracket. This means taking anywhere between 3 and 5 different exposure values of the same image. One correct exposure and then over and under exposed by 1 and 2 stops. I would strongly recommend using a tripod and shooting in RAW. If you take your photography seriously you should always shoot in RAW – even if right now you aren’t using or editing those files.
When shooting try to work quickly and shoot with similar lighting which may be difficult with landscapes if it suddenly becomes overcast or sunny. Clouds and plants also move pretty quickly on windy days. When putting the images together later it will cause ghosting from the different objects not being in the same place in each photo. That’s why the tripod is important. There may be similar difficulties with motion blur and ghosting on longer exposures. You want each of the 5 images to be as identical as possible so they line up properly.
 
Step 02: Pre-Processing
 
It’s definitely a bit tedious if the image is made from multiple shots, but it is possible to create them from one correctly exposed RAW file so you don’t have to worry about ghosting from any moving objects. You wont get all the dynamic range you can get from shooting multiple images but you can still get a similar effect.
When processing the RAW file export an image at the EV values of -2, -1, 0, +1, +2. For more on this see my previous post [Explaning Exposure]

EV -2EV -1EV 0EV +1EV +2
For demonstration purposes i’ll be using this one exposure method.
   
Step 03a: Processing in Photomatix
 
The first thing you do is load your bracketed photos [3-5 photos].


If the different photos were made from one file the meta info will have the same exposure value recorded for how it was shot. You will need to manually fill in the exposure value and the increments at which they were adjusted to. I did them in whole stop increments from -2 to +2.
 

 
When you press “ok” it will give you a few options for automatically dealing with several things, such as alignment and ghosting. I didn’t need to check any of these since I did mine off the same image.



It will then composite a preview image that you can adjust. The screen will look like this:

[click image to enlarge]
 
There are several detailed settings on the left and the filmstrip along the bottom contains various presets that you can apply and then fine tune on the left panel. You can use the loupe to magnify details. The top bar has all the zooming/viewing options, and there is a histogram toolbar as well.
 
The settings you decide on will depend on your taste. Some people love the “painterly” look and some hate it because it starts to look more like a painting than a photograph. Reducing the “smoothing” setting will increase the effect while increasing it will reduce it. The rest of the settings are best explored depending on the photo and what look you’re going for.
 
Step 03b Processing in Photoshop:

This step is more advanced. You need some familiarity with layers & blending modes and layer masks. First, open the correctly exposed image [EV 0]. Then “Place…” the underexposed images over the the original layer and place the over exposed images on top of those. If you need to adjust the alignment you can do so as you place each image by reducing the opacity of the placed layer and moving the layer until it matches the one under. ghosting elimination will come later.

        
You can play around with different layer orders and opacities – even blending modes – but i recommend setting any underexposed images to “Mulitiply” and overexposed images to “Screen.” Mulitply blends only the dark values into the final image composited and Screen only blends in the light values. this way your correctly exposed base image is being enhanced by the values in other images.
 
You can get even more tones values by using other filters such as “Diffuse Glow” and a Layer Mask to hide and reveal dark and light parts of each layer.
The Diffuse Glow settings I used are below, but yours may vary. You just want it to have a a soft glowing effect on the highlights. The final touch for this layer is to set it to screen mode and adjust the opacity as desired.
 

 
I added a bit of a vignette by using a copy of EV -1 layer in multiply mode over the screened layers and then using the layer mask to hide the center of the layer with a large brush in black.


 

The Results.
[click images to enlarge]
 
 The images that are done manually aren’t as detailed and simply have an HDR effect, but it is possible and actually more time consuming in comparison… After trying Photomatix i highly recommend it. I know a lot of others do too.

I’ll do a proper HDR image later on to show how color can be exaggerated, and how the results from multiple images differ and are ultimately better.