Jump to content

SF-58 Flash Newbie - A Little Help Please...


Three Legged Cat

Recommended Posts

Advertisement (gone after registration)

Hi All,

 

I have just taken delivery of an SF-58 Flash to use on my M240, and I'm struggling a little. Although I have never used a flash before, I'm not asking about Flash techniques, comparison with other Flash Units etc.; my problem is understanding what the Flash is actually doing, and what & when I should be altering things on the camera and/or flash.

 

To keep it simple, I have set the SF-58 on my M240 + 50mm Summilux on a tripod in my cellar 'studio', ca. 5m x 5m, white walls & ceiling with recessed LED lighting. Initially I wish to use flash simply in 'TTL' mode to photograph portraits of family/friends/kids etc. before doing anything more interesting.

 

So, the camera is in 'A' mode, ISO set to 200, and I'm standing about 2m from my subject, and I've selected 'f8' on the lens. The viewfinder shows '45' and the flash symbol is shown, and the image is razor-sharp. So far, so good...

 

Now the back of the SF-58 shows 'TTL', 'f4', '<Symbol for 'secondary flash>', 'AZoom', and 'EV +1'. I angle the main flash to 60 degrees and take the shot; the flash discharges, the red light shows on the back to say exposure is fine, and the image looks...Good!

 

But this is the problem - I don't understand what just happened: Did the camera tell the flash the ISO? the Aperture value? The distance to my subject? Did the camera fire the secondary flash based upon it's own calculation to 'fill-in', or did it just do it 'dumbly' as it would every time because I selected it - or do I have to do 'something else' to make it fire?! Has the camera selected '45' because I am using a 50mm lens or is this the default speed for TTL? Should I select the flash-speed of 1/180 instead? So many questions!

 

Having read the maul, I believe that the ISO information is Automatic, as is the focal length information (AZoom = 50...) - but must I set the Aperture on the Flash manually to match my camera for every shot? This is the crux of my problem; the back of the flash says 'f4', but I've selected 'f8' on the lens and the photo turned out OK. Is the flash unit 'advising' me to select 'f4', or do I need to adjust it manually to match my selection on the lens before firing? Also, does the flash 'know' I'm 2m from my subject and is readjusting itself accordingly?

 

To put it bluntly, I don't know how 'clever' this Flash is, and how much input I need to make prior to pressing the shutter. I'm sorry if these questions appear stupid, but I'm really struggling to get my head around all this.

 

I'm sure if I didn't think too hard about it I'd probably get the odd decent result, but I really want to master the 'Art of Flash' eventually. However, until I can comprehend exactly what the Flash is doing and what I need to be doing in response, I fear I'll never get there. The Manual is just not clear enough for me, and reading around the subject a great deal of prior knowledge is assumed. I'd be grateful for any input to explain what's going on.

 

Thanks in advance and Regards.

Link to post
Share on other sites

You are correct that your camera "tells" the SF-58 the ISO setting, but that information ias well as lens aperture) is not used by the flash in TTL mode. In TTL the flash emits a small pre-flash that is used by the body to calculate the flash output needed to achieve correct exposure. So in this mode the flash is essentially dumb - all calculation being done in-camera.

 

If you put the SF-58 into A mode it is a different story. In this mode the flash is smart and the camera dumb. The SF-58 receives the ISO from the camera, but the lens aperture must be manually entered by the user. It this point when the shutter is released the flash fires and then monitors the light reflected from the subject shutting off its output when proper exposure is achieved.

 

Both modes are useful. TTL works well most of the time, but can falter in situations where the camera's metering is "fooled" by the lighting situation. For example with a back lit subject the camera may respond to the background and seriously underexpose the subject. In A mode the flash would normally ignore the background light level and properly expose the subject. Since there is no pre-flash in A mode it is also useful for subjects who tend to blink when in TTL mode.

Edited by Luke_Miller
Link to post
Share on other sites

Thanks Luke - your explanation makes a lot of sense. I had already been reading about A-mode, and figured out that it might be the way forward for me in that it seems more 'logical' in how it operates.

 

Initially I was thinking of the TTL-mode it as a kind of 'Super-Auto' mode where the Flash was making all the clever calculations based upon the set-up of the camera; however the fact that the 'f4' on the back didn't accord with my selection on the lens left me baffled, and that to have to then input the aperture manually in this mode seemed to defeat the purpose of having a 'TTL mode' in the first place! I think I'll explore the A-mode further, and just be guided by my results until I have more experience.

 

Anyhow, your input to my somewhat long-winded question is greatly appreciated...

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...