Why are my pictures dim? (Discussing Flash Exposure Compensation)

A diffuser takes a narrow, concentrated beam of light and distributes that light across a larger area. We have to adjust for this by increasing the light output of the flash. Some automatic modes will make this adjustment correctly but we recommend using flash exposure compensation (FEC) to fine tune it. When firing the flash straight towards your subject, the camera’s TTL calculations are based off that concentrated beam of light and does not take the dispersed light fall off into consideration. A simple FEC adjustment can bump up the flash power to properly light your subject. By adjusting FEC you have more control over the exposure of your pictures.

On the other hand, when using a flash in bounce mode through a diffuser, the TTL anticipates the light loss and compensates. The diffuser makes the camera’s TTL think that the walls and ceiling are farther away than they really are and the flash automatically increases the flash power.

For Graslon Flash Diffusers we recommend adding 1 2/3 to 2 stops of FEC in normal portrait distances.

To see how to change FEC on your camera or flash, check out these tutorials that show how easily and quickly FEC can be changed on Canon and Nikon bodies, as well as on the flash.

Canon Bodies

Nikon Bodies

On the Flash

Changing Flash Exposure Adjustment for Canon Bodies:

For most Canon DSLR bodies there is an exposure compensation (FEC) button.


Press the FEC button and then turn the quick control dial on the back of the body to set your desired FEC.


For Canon DSLR bodies that have the Quick Control screen (60D, 70D, and 6D)


Press the [Q] button to bring up the Quick Control screen and then select the FEC icon.


Use the main dial to select the desired amount of FEC then press the SET button.


For Graslon Flash Diffusers we recommend setting the FEC to +1 2/3 to +2 in normal portrait distances.


If this does not work for your particular camera, please consult the manufacturers instruction manual.


Be sure to set the FEC back to zero when not using a diffuser.

Changing Flash Exposure Compensation for Nikon Bodies:

For most Nikon DSLR bodies flash exposure compensation (FEC) can be adjusted by pressing and holding the flash button and then turning the sub-command dial (located near the shutter button) until the desired FEC is selected.


If your Nikon does not have a sub-command dial, then press and hold the flash button and the exposure compensation button together.


While still holding the two buttons, turn the main command dial (located on the back of the body) until the desired FEC is selected.


The adjustments will be shown on the screen


For Graslon Flash Diffusers we recommend setting the FEC to +1 2/3 to +2.


Most Nikon bodies limit FEC to +1. In this situation we recommend increasing the exposure compensation +1 as well. The can be changed by holding the exposure compensation button and turning the main dial. Alternatively you can set the flash compensation on the flash instead of on the body.


If this does not work for your particular camera, please consult the manufacturers instruction manual.


Be sure to set the FEC back to zero when not using a diffuser.

Changing Flash Exposure Compensation on the Flash


For most flashes, flash exposure compensation (FEC) can be set by pressing and/or holding the [SEL] button until the FEC icon is flashing in the display.


Then press the [+] or [-] or turn the dial to select the chosen FEC.


the FEC adjustment will be displayed on the screen. Then press the [SEL] button to confirm your selection.


Be sure to set the FEC back to zero when not using a diffuser.


If this does not work for your particular flash, please consult the instruction manual.

Mounting Instructions

Graslon’s mounting system is truly a revolutionary way to attach flash accessories to external strobes, we are very proud of this groundbreaking method.  The initial setup really is a simple process if the steps are all done in the proper order. Check out our instructional mounting video.  

Here are the steps:

Step 1:  Loosen the thumb screws and the Strap.  The four brackets should be free to move freely.










Step 2: Open the Brackets and Insert Flash










Step 3:  Tighten and Secure the Strap.  This will move all four brackets at once around the flash.  Really give the strap a good tug!  Don’t be shy!










Step 4:  Center Diffuser on the flash before tightening the thumb screws.










Step 5:  Tighten thumb screws.  Now the Diffuser can be attached or removed and only needs to be readjusted if fitting to another sized flash.











Troubleshooting Tips:

-The diffuser should be held onto the flash by the rubber pads.  If the pads are not contacting the flash the flash may be too far in.  There are some small “stops” on each bracket which keep the flash from going too far in.

-The strap needs to be tightened while the thumb screws are loose.  Once the strap is tight, tighten the thumb screws.

-Sometimes folks do not pull the strap tight enough.  If your diffuser is loose, fix it by loosening the thumb screws again and really tightening that strap.  Then retighten the thumb screws once the strap is tight and secure.


Lighting Basics: Controlling Background Exposure with Shutter Speed

Here is a simple technique that, with practice, can give you greater flexibility in your pictures.

In the following photos, notice the difference in the exposure of the background. The slower the shutter speed, the lighter the background; however the exposure on the subject remains constant. How is this possible?

In order to achieve these results, the following conditions must be met:

  • The background must be far enough away so as to not be affected by the flash. In other
    words, the background must be “out of range” of the flash.
  • The subject must receive most of its illumination from the flash.

If these two conditions are met, here is what you can achieve by simply changing your shutter speed and exposure:

The subject is exposed from the flash, while the background is exposed from ambient light. By changing the shutter speed (keeping within flash synch speeds) the exposure on the background will change. However, changing the shutter speed will not change the exposure on the subject, since the slower shutter speed (1/250 second or slower) will always let the entire duration of the flash (1/1000 to 1/4000 second) through the shutter.

Remember the five components of exposure for flash photography: ISO, aperture, shutter speed, flash power, and flash distance to subject. You can use these characteristics to control exposure in different parts of your scene. The shutter speed only affects the parts of the picture that are out of flash range. The flash power and distance only affect the components that are within the flash range.

In these photos, aperture, ISO, and flash power were kept constant. The photo with the darkest background was taken at 1/250 shutter speed. The photo with the brightest background was taken at 1/30 shutter speed. Give this a try on your own; it’s a lot of fun to play with.


Hint: Many times it is acceptable, even desirable, for the background to be blurry, so you may want to use very slow shutter speeds to brighten the background.

Hint: If your background is too bright, use a neutral density filter to darken everything and increase flash power.



Graslon Photo Contest Results!

Here are our contest results. We hope to hold many more photo contests. If you missed this one and want to be included in the next email a photo that was taken using a Graslon diffuser to Chris@graslon.com. I’ll make sure your entry is included in the next one!

Frog with Spark

Frog with Spark

Our first winner shown to the right is Jason Butler who took a great picture of this frog in Southern Alabama using his Spark. Great job, and congratulations to Jason for winning a his choice of a new Prodigy, Insight + Spark, or 3 new Spark diffusers!

Amelia with Prodigy

Amelia with Prodigy


Our next winner was Scott who took this great shot of his beautiful granddaughter using his Prodigy with the Domed lens. Congratulations to Scott!

Graslon Kickstarter Photo Contest Results

Last fall we did a Kickstarter campaign to kickoff our new product, the Spark, our popup flash diffuser. We received a huge amount of support both during and after the campaign. It was a fantastic experience for us. We decided to hold a photo contest open exclusively to our 153 kickstarter backers. Visit our kickstarter page below to see our video:


Graslon Spark at Beach


Our first winner shown to the right is Paulette out of Los Angeles and Brazil. She sent us a fantastic photo using her Spark. She was able to supply a nice amount of fill lighting on the subjects and captured a beautiful sunset just before it went down. Great job, and congratulations to Paulette for winning a her choice of a new Prodigy, Insight + Spark, or 3 new Spark diffusers!

Flower in Evening

Flower in Evening


Our next winner was Travis out of Niagara falls Canada who took this great shot of a flower in the early evening using his Spark diffuser. I think it turned out quite nicely. Congratulations to Travis!

Zoom, Zoom!

1962 Corvette

1962 Corvette

One of the truly great things about photography is the ability to capture people’s passions. This amazing 1962 Corvette was perfect to the very last detail, exhibiting the owner’s enthusiasm for this vehicle.

The photos displayed here show some of the advantages of using a soft light source as outdoor fill. Often in these situations there are regions of a picture where you simply need more light.

1939 Chevy

1939 Chevy

Here is a 1939 Chevy. The mid-afternoon sun leaves the engine compartment in the dark. Photographing the engine while maintaining  proper exposure on the exterior requires a little help.

39 Chevy no flash

Taken with no flash

This was taken with no flash.Part of the engine is in bright sunlight and the rest is in the shadow. Click on the photos to see more detail.

39 Chevy direct flash

Taken with direct flash

Adding fill from an on-camera flash balances the exposure nicely. Notice, however, the shadows from the support bar, wires, and radiator hose, etc. Exposure is good, shadows are not.

39 Chevy Graslon 4100F

Taken with Graslon Prodigy Flat

This was taken with the same flash with the Graslon Prodigy with Flat lens. Notice the shadow from the support bar has all but disappeared, and the other shadows are much more natural looking.

The Graslon diffusers can be used virtually anywhere a flash is needed, with superb results.

Open Shade a Snap!

tortoise no flash

No flash

Photographing subjects in open shade can be a challenge. The first picture of the tortoise was taken with natural light in mid-afternoon with very bright spots in the background and very dark areas on the subject.

tortoise direct flash

Direct flash

The next picture was taken with direct flash. The dark areas disappear, but the harsh shadows look like- a flash picture. Not the greatest.

Taken with Graslon 4100F flash diffuser

Taken with Graslon 4100F flash diffuser

The last picture was taken with a Graslon 4100F diffuser. Notice how natural the subject looks, and the dark areas are nicely lit with soft, even light.