Monday, April 20, 2009

Comparing Guide Numbers for Strobes

The guide number (GN) for a strobe light tells us the ability of the strobe to light the subject based on the ISO and angle of view. So, just by comparing GN from one flash to another is not enough. You would also need to compare the ISO and angle of view that they have measured from. Because of this, strobe manufacturers can publish that they have a high GN, but if you do not see the ISO and angle of view at which they measured it, you could be fooled by their marketing scheme.

Take for example...

Nikon SB-80DX - GN 38m (ISO 100, 35mm)
Nissin Di622 - GN 44m (ISO 100, 105mm)

At first look, you would think that the Nissin Di622 is more powerful than the Nikon SB-80DX. But at 105mm, the GN for the Nikon SB-80DX is 56m. Hence, the Nikon SB-80DX is actually a more powerful flash than the Nissin Di622.

The GN for the Nikon SB-80DX speedlight are as follows with reference to the angle of view...

14mm - 17m
17mm - 19m
24mm - 32m
28mm - 34m
35mm - 38m
50mm - 44m
70mm - 50m
85mm - 53m
105mm - 56m

To understand more about GN, you can refer to Wikipedia's Guide Number or Flash Guide Numbers by Dennis Curtin.

Thursday, April 16, 2009

Shoot-Through Umbrella vs. Softbox

What is the difference between a shoot-through umbrella and a softbox? Zack Arias explains it in his blog and the following 2 pictures were taken from it. Have a read at this great article here.

Friday, April 10, 2009

The Apollo has landed!

The Apollo has landed!

After much deliberation, I decided to order a Westcott Apollo 28" Speedlight Set from B&H. James was ordering a number of stuff from there... so I tagged along on his order, and he also ordered one for himself.

At US$119.95 + shipping, this does not come cheap. The speedlight set comes with a hotshoe umbrella adaptor. It has the same internal concept as the umbrella softbox, but the advantage is not only the size, but it has a recessed front to control the spread of the light.

I shot a few shots at a low 1/128 power on the Nikon SB-80DX, and the light that came out was even throughout the white area. Comparing to the umbrella softbox, the Apollo gives a more even distribution of light. This is likely because of the larger volume interally where the speedlight can be placed further from the silver reflective area, and also a larger area for light to bounce internally.

I particularly like the design where there is a cross zipper area to accomodate for the lightstand to go through into the softbox. The volume inside the softbox is large enough to contain a monobloc light.

Here are 2 pictures of the Apollo Speedlight Set, the first showing the internal construction and how the speedlight is mounted, and the second is the external showing the recessed front.

Thursday, April 2, 2009

Rocky & Juana's Pre-Wedding Photoshoot

I have not been blogging here for awhile, and one of the reasons is that I've got a hold of a copy of The Hot Shoe Dairies and am reading it! The other reason is not that cheery... and it is that I've been sick for more than a week. Despite being sick, I wanted to go do some shooting, so I tagged along as my friend James did a photoshoot for Rocky & Juana.

It was certainly not a good day for me to shoot. I realized that because of my flu, my brain was half-dead and somehow did not shoot well nor liked what I shot. This really set me thinking... should a photographer shoot well only when he is inspired? I believe photographers have bad days, and sick days, but if they are contracted to do a shoot, should they not be able to produce even if they did not feel like 100%?

This made me realize that every photographer must get as much in his "bag of tricks" that whether it was a good day or not, he should be able to produce a minimum standard in his shots... and getting the "bag of tricks" is something I had to work at. I must say that this is the worst shooting day I've had so far... but it is spurring me on to get my "bag of tricks" for the future!

Oh... by the way... the above shot was done with 2 strobes... one at the far end with a Gary Fong Lightsphere to light that area, and the other is on the camera left with a softbox umbrella to light Rocky and Juana.