Thought i'd start a new thread instead of adding to the PLM ones...
I'm looking forward to this new modifier as it will be the first beauty dish i play with. Here is my question....
If the estimated beam spread (according to Paul's reports) is around 45 degrees, and the current 22" grid is supposedly 40 degrees, will the grid shape the light in ways other than an additional 5 degrees?
Paul Buff wrote:
Yes, the 40° grid will sharply cut off the light pattern. Without it, the light feathers out to 150° or so. We will do narrower grids in the future.
Sorry Paul, this statement confuses me, the new web page says: " The 22HOBD is designed to project a narrow 45° beam angle."
How does the 150° fit in there (unless using the sock, as stated on the page)
from the web site (so the 150 is with the sock);
The 22HOBD is designed to project a narrow 45° beam angle, with about six times the efficiency of a white dish. This allows for lighting subjects from greater distances with low power flash units, and allows using the reflector with or without the included direct-light blocker.
Attaching the included diffusion sock converts the 22HOBD into the equivalent of a round softbox with very even coverage and outstanding evenness across the face of the diffusion fabric. This widens the angle of coverage to about 150° and lowers the output by about 1 1/2 f-stops. It also minimizes the specularity and results in approximately the same photographic result as a conventional white beauty dish with diffusion sock.
gpsphoto wrote:
If the estimated beam spread (according to Paul's reports) is around 45 degrees, and the current 22" grid is supposedly 40 degrees, will the grid shape the light in ways other than an additional 5 degrees?
Someone please correct me if I'm wrong, but I don't think the spread of an unmodified light affects its spread when fitted with a grid (unless the grid allows for a wider spread than the light actually produces, of course, if you wanna get technical). For a testable example try putting a 20˚ grid on a speedlight (580EX or SB-800, e.g.) and zooming the head to different coverages. The spread of the beam should not change, although the intensity will (assuming constant output and distance to wall/subject).
Every reflector has a beam width that is specified as the angle at which it produces 1/2 power (-one f) relative to the center. They also have light outside this area that is lower than half power . . spill light outside the main pattern. Sometimes this is useful and sometimes not desired.
A reflector like the BD is shallow, thus has a wide angle of forward spill. Even a deep dish has the same effect, but the spill pattern is narrower because the edges of the reflector block more of the unfocused light from the tube.
A honeycomb grid eliminates this spill.
The 150° beamwidth of the BD with sock is the area it lights within the 1/2 power point . . . same for any softbox without grid . . . same with any flashlight.
Regarding plastic . . . there is no plastic in either the BD or the grid. They are both aluminum so they don't melt or deform under heat. Narrow aluminum grid material is very expensive, regardless of where it comes from.
I will have pictures of the 22 High Output BD very soon. Competent technical help is very hard to come by these days. Seems like everyone wants to work for Microsoft or the government! Maybe my standards are too high.
The 22" grid has spring protrusions that hold it in the BD with friction. It's very secure.
Thanks Paul! I had forgotten how the beam angle measurement was determined...
For the sake of discussion (and to try and wrap my brain around the numbers...), if each modifier had a secondary beam width value that represented 1/4 power relative to the center (further out into the spill zone) a standard BD might look like this:
Will this be replacing the current matte-white BD, or augmenting it?
Are you going to have your new manufacturer produce the matte-white version in the near future? ( I recall you mentioning a new vendor for the silver version)
Also, are the grid spots interchangeable between both BD generations?
I just recently purchased the matte-white version, and I am really happy with both the build quality AND the light quality. I need a good travel case, though.
Hey Paul, quick question before I snap up your new BD (which, BTW, you should put a link to on your main PLM page, since that's where people are expecting it to show up):
Is the output increased considerably (more than 1/4 stop) when the deflector is removed?
And how does the overall output compare to the 11'' sports reflector?
At 10-20', there won't be a huge difference between the apparent size of an 11'' and a 22'' reflector, so I can see a sports/high output/Magnum reflector working well with that BD in a key/fill application.
gpsphoto wrote:
Thanks Paul! I had forgotten how the beam angle measurement was determined...
For the sake of discussion (and to try and wrap my brain around the numbers...), if each modifier had a secondary beam width value that represented 1/4 power relative to the center (further out into the spill zone) a standard BD might look like this:
1/2 power = 145 degrees
1/4 power = 165 degrees
but with a grid it would basically be
1/2 power = 140 degrees
1/4 power = 142 degrees
That would be a 140° grid. With a 40° grid the light should pretty much stop outside of 40° - 1/2 output at 40° then a rapid falloff to nothing.
Remember, to properly measure wide angles, you must measure in an arc around the light unit, not against a flat surface.
