Strobe questions

[f3nikon]

i have the same shadow problem with the oly c-765 and the oly sp-550uz when using the internal flash. you have to take the picture farther away to avoid having the shadow. but then that beats the objective of having less water between the lens and the critter.

I agree on the less water but again I do not know if the Olympus SP-550UZ is the same setup as the Canon A630/640 diffuser.

 

[Gilligan]

Something else to consider in this discussion which I also want to confirm is the ability/inability of a particular camera brand/model to zoom in the macro mode. This may be an important factor in the dark areas of the photo.

For example, My Oly C4000Z has zoom capability in the macro mode. This allows me to back away from the subject and still fill the frame and give enough distance so as to have the internal strobe light up the entire subject. This scenario especially comes into play when I find a subject that is down in a coral head and the camera cannot get close enough without zoom capability.

Correct me if I am wrong but the Canon A630/640 does not have zoom capability in the macro mode? The lens is fixed at wide angle so you have to move the entire camera too and from the subject to fill the frame. This may cause the camera to be too close to the subject resulting in the dark area that the internal strobe cannot fill.
Of course a solution to this is backing away from the subject then cropping the photo after the fact so that it fills the frame. The A640 at 10 megapixels should make cropping a simple procedure without much pixel loss, something I cannot do with my 4 megapixel Oly.

I have taken several pics using only the internal strobe and the housing diffuser and have not experienced the dark spot unless I get too close using my Inon UCL-165 macro lens.

This pic was taken using the internal strobe. The dark area above the crab is from the overhang of the crevice.

 

[jaybombs25]

So basically since I mainly plan to take macro shots with my camera, the best thing for now would be to try it out with the diffuser right? or i'm i missing something here? Thanks..
Also does the diffuser come with the housing? or is that a separate buy?

 

[jigo]

yes the diffuser helps a lot. best if you try your set-up first and see what works.

my oly sp-550uz also has a huge diffuser way up front parallel to the lens port but shadows are inevitable if pics are taken too close to the subject. most oly can zoom using macro mode but lens are fixed and there is no flash if in super macro mode. problem with zooming is it is more sensitive to camera shake and takes longer to focus without a light.

 

[shugar]

I am not sure which Canon you are using but the 630/640 has the best and most number of power settings I have seen in a PS, +/- 2 full stops at 1/3 steps, thats about 10 or more settings plus full aperture control, the 630/640 has more than enough light control.

And backscatter with NOT go away if the light is NOT parallel to your lens, the backscatter is still there causing your image to be grainy or fuzzy, even without a strobe or flash. The really way to reduce backscatter is to move the camera closer to the subject.

i use a 620 w/c is generally a 640 w/ 3 less megapixels and an LCD w/c has a 3:4 aspect ratio...

i don't mean exposure compensation... i meant strobe power... only 3 levels for the canon... strobe power is strobe power, exposure compensation is exposure compensation, aperture is aperture... although you may get similar results they are not the same

Jag

 

[f3nikon]

i use a 620 w/c is generally a 640 w/ 3 less megapixels and an LCD w/c has a 3:4 aspect ratio...

i don't mean exposure compensation... i meant strobe power... only 3 levels for the canon... strobe power is strobe power, exposure compensation is exposure compensation, aperture is aperture... although you may get similar results they are not the same

Jag

"only 3 levels for the canon"...are you sure? Each of these shots had a different strobe power level for which I controlled 13 power levels total. This is the reason I do NOT use TTL, I want full control of the strobe level that I feel is correct to my eyes.

Also: "although you may get similar results they are not the same" please explain (this is not a trick question).

 

[f3nikon]

Something else to consider in this discussion which I also want to confirm is the ability/inability of a particular camera brand/model to zoom in the macro mode. This may be an important factor in the dark areas of the photo.

For example, My Oly C4000Z has zoom capability in the macro mode. This allows me to back away from the subject and still fill the frame and give enough distance so as to have the internal strobe light up the entire subject. This scenario especially comes into play when I find a subject that is down in a coral head and the camera cannot get close enough without zoom capability.

Correct me if I am wrong but the Canon A630/640 does not have zoom capability in the macro mode? The lens is fixed at wide angle so you have to move the entire camera too and from the subject to fill the frame. This may cause the camera to be too close to the subject resulting in the dark area that the internal strobe cannot fill.
Of course a solution to this is backing away from the subject then cropping the photo after the fact so that it fills the frame. The A640 at 10 megapixels should make cropping a simple procedure without much pixel loss, something I cannot do with my 4 megapixel Oly.

I have taken several pics using only the internal strobe and the housing diffuser and have not experienced the dark spot unless I get too close using my Inon UCL-165 macro lens.

This pic was taken using the internal strobe. The dark area above the crab is from the overhang of the crevice.

Good point and good example with an external strobe, the rock above the carb would have been blasted to over exposure and the carb would be mostly in the dark. To answer your question...yes the macro will work in the zoom mode...but limited to only a narrow range.

 

[bobf]

...are you sure? Each of these shots had a different strobe power level for which I controlled 13 power levels total. This is the reason I do NOT use TTL, I want full control of the strobe level that I feel is correct to my eyes.

Flash compensation has been exhibited in the above series of exposures........and in doing so you are relying on TTL and not full manual strobe control. In flash compensation the user may only have the ability to influence the camera's decision........+- 2 stops as shown in the example above.........which is based primarily upon the camera's metering system.

In other words, flash compensation begins with the camera first dictating or deciding what it assumes to be an acceptable flash exposure. Flash Exposure Compensation then allows the user to modify or influence the camera's decision by +-2 stops.

Full manual strobe control is described as the user having sole control.......without influence. The only way for you or anyone to achieve "full control of the strobe level" of the onboard strobe's output with the above equipment is by choosing one of three manual power levels as mentioned by Jag.........and as most likely described in the Canon user's manual.......and in the below link (scroll down the page to "other flash functions").

http://www.dirtcheapcameras.com.au/store/product.asp?idProduct=844

 

[walkerl]

While this is a very interesting discussion and one I can learn a lot from, I have the same original question that was posted. I have the Canon Powershot A640 with the same housing and am thinking about getting a strobe. I would like to get a good strobe now so that if/when I upgrade to a DSLR, I can simply transfer my strobe. Are all "good" strobes capable of the crossover or are some strobes more camera specific. Did anyone get annoyed by how many times I said strobe?

Thanks,
Walker

Strobe

 

[PriusDrIVER]

As for which strobes are compatible...that all seems to come down to what SLR and housing you have and if TTL is important to you. Each housing seems to be proprietary on their TTL options. Each housing brand only offers housing for certain camera brands/models. If TTL isn't important, then its more flexible...as almost any housing can provide a trigger for almost any strobe. Its just if you want the camera to have access to control the strobe is where it gets complicated.

I'm going through this now, I'd prefer Sea&Sea (or Inon?) strobes but have an Ikelite housing. The Ikelite housing has integrated TTL, but it only works with Ikelite strobes. So I have to either shoot manual mode on a Sea&Sea/Inon or TTL on an Ikelite.

Strobes that offer optical trigger/slave can be more flexible, if you find a housing that allows the use of the internal flash then it will work. Its when you get to circuit tied TTL that things don't coexist very well. As for strobes with optical slave options, I believe Inon and Sea&Sea are the bit options...though, again...I'm new and doing research myself.

So, the answer is "yes, all good strobes /might/ work with a P&S or SLR"