Camera flash pulses are typically very fast. It is fast enough to freeze motion even if you use a very slow shutter speed as long as the light from flash dominates the exposure.
Most camera flashes have xenon flashtubes. It lights up when the charge stored in a capacitor is discharged through xenon gas. The xenon gas is not very conductive in its normal state but its resistance can be greatly reduced when the xenon gas molecules are ionized, ignited by a high voltage pulse. The charges stored in the capacitor start to flow through the tube, giving out a very bright light. As the charge stored in capacitor discharges, the light intensity decreases.
The light intensity during a flash pulse isn’t constant. The light intensity emitted from the flash tube rises to a maximum quickly then fall off. If the charges stored in the capacitor are allowed to completely discharge, the light intensity will show a graduate reduction tail. Since we don’t want full power flash for each shot but rather just the right amount of light for proper exposure, the flash unit cuts off the discharge circuit at different times to control the amount of light emitted. Lower flash output power means shorter flash duration. Read More…
The flash output level of a Nikon SB-600 Speedlight Flash can only be set to the minimal of 1/64 in manual mode. That leads many people to speculate the minimal output from the flash is 1/64. If you have used the Nikon Creative Lighting System (CLS) Advanced Wireless Lighting (AWL), you will know that you can use 1/128 output setting on the wireless commander unit. The wireless commander can be the built-in flash of your camera, or SU-800 commander, or SB-800/SB-900 Speedlight flashes. The question is what happens when the remote flash is a SB-600. Will it actually output 1/64 or 1/128 of light when the commander tells it to do 1/128?
To answer this question, I ran a test with a flash light meter to measure the output of the SB-600. Read More…
Before I got my first true Macro lens, a Sigma 105mm f/2.8 EX DG, I had a cheap way of getting macro shots: Mounting a Nikkor 50mm f/1.8D AF reversed using a reverse ring (Nikon BR-2A or the cheaper clone). The picture of that setup and sample image can be found here. Basically it worked OK. On my D200, the camera maintains auto-exposure but no more auto-focus. The images are quite sharp. The magnification is not high through.
Recently I acquired the 35mm f/1.8G AF-S DX, which is a nice prime lens for DX format Nikkon DSLR cameras that gives you a “normal” field of view. When I stumbled across the reverse adapter ring I purchased long time ago on a dusty shelf, I decided to try it with the Nikkor AF-S 35mm f/1.8G lens. Read More…
The question got asked quite often on the internet lately. Is it possible to mix TTL Flashes with non-TTL manual power flashes or strobes so they sync together? For example, one guy wanted to fire two SB-900s in wireless TTL mode while also triggering an Alien Bee studio strobe at the same time.
The answer is Yes. Since I have only Nikon DSLR and Nikon Speedlight flashes (D200, SB-800, and SB-600), I can only describe what’s possible for people in similar situation. For your particular Camera/Flash brands you will need to decide if this method works for you. Read More…
Shooting the mysterious Moon is a frequently discussed photography topic. For a Moon in a cloudless sky, the shooting pretty much is a matter of trivial exercise in term of exposure determination. We have some general tips for moon shooting. The following is the Moon shot with 1/640s f/8 and ISO 200.
It becomes challenging when you want to photograph the Moon behind the veil of the clouds. The reason? At night the Moon is so much brighter than the clouds, a proper exposure of the clouds will pretty much gurantee a blown-out Moon, just like the title image of this post, which was shot with 1/3s f/3.5 at ISO 200 -0.7EV. (It may be a good practice if you want to count the exposure differences between the two shots in stops or EV.)
Are there ways to preserve the details of the Moon surface while properly exposing the clouds? Read More…
In the previous post about front-curtain and rear-curtain sync modes, I used a two-exposure model to describe the final image created by the contribution of both ambient and flash lights. In this post, I will go into details about the shooting parameters that affect both exposures and the most effective techniques of balancing flash and ambient exposure. I will mostly speak in Nikon terms since that’s the only brand of DSLR camera I have access to.
Four parameters
The four camera parameters that affect the final exposure are: ISO, aperture, shutter speed, and flash output amount. If the camera and flash are in full manual mode, all four parameters can be freely adjusted by the photographer. In the chart below, a check mark is used to indicate that the particular camera or flash parameter affects ambient or flash exposure. “–” means it does’t. An important assumption is made here: Flash duration is so short compared to shutter speed that shutter speed does not affect flash exposure. This excludes the FP high speed sync flash mode from our discussion to avoid complications. Read More…
Many new digital SLR cameras now come with a feature called Auto ISO, which automatically adjusts the ISO sensitivity of the camera based on pre-programed algorithms and user preferences such as maximum allowed ISO and minimum shutter speed.
Is this feature useful?
The typical support argument for the Auto ISO feature goes like this: Camera lenses have the maximum aperture limitation. At a given ISO, the required shutter speed to achieve proper exposure may be too slow to stop motion or avoid camera shake even when the aperture is at its maximum setting. In this case, the ISO setting of the camera needs to be raised until a usable shutter speed can be obtained. This previously human-involved process can be automated by the Auto ISO feature.
Still need to see some more convincing arguments or have some questions answered about the usefulness of the Auto ISO feature? Professional photographer Steve Simon shared his thoughts on the Auto ISO feature in Nikon DSLR camera in two discussion threads on Flickr:
can only be set to the minimal of 1/64 in manual mode. That leads many people to speculate the minimal output from the flash is 1/64. If you have used the Nikon Creative Lighting System (CLS) Advanced Wireless Lighting (AWL), you will know that you can use 1/128 output setting on the wireless commander unit. The wireless commander can be the built-in flash of your camera, or SU-800 commander, or SB-800/SB-900 Speedlight flashes. The question is what happens when the remote flash is a SB-600. Will it actually output 1/64 or 1/128 of light when the commander tells it to do 1/128?
, I had a cheap way of getting macro shots: Mounting a 
reversed using a reverse ring (
, which is a nice prime lens for DX format Nikkon DSLR cameras that gives you a 
