Beginners Help Wanted

[cold-chilli]

Hi all.

I've recently decided to give photography a bash after viewing so many amazing photos on various different websites. Not having much knowledge I followed a tutorial on droplet photography. Although I ended up with some good results I am baffled by a few that I don't understand how they turned out like they did.



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I have an SB-24 off camera to the left with a set of ebays finest wireless triggers. The flash is pointing at a white background.

Sony Alpha A200
Nikon SB-24
ISO 400
Exposure: 0.25 sec (1/4)
Aperture: f/10
Focal Length: 27 mm

If anyone can help me understand why this happened I would be hugely greatful.

Many thanks in advance.

James

[OsmosisStudios]

Well, the shot is overexposed for one. ISO 400 at 1/4 second, even at f/10, is gonna be bright

As for the black strip: usually that means your sync speed with the flash was too high. Most cameras only sync to 1/200 or 1/250s shutterspeeds and so the entire frame isnt illuminated by the flash, but at 1/4 that shouldnt be the case.

[inkista]

Flickr is giving the shutter speed as: 0.004 sec (1/250)

Which is 1/250s, not 1/4s. There's no way you would've frozen the action on that waterdrop like that at 1/4s.

You're over your A200's max. synch speed (1/160s).

Basically, with a focal plane shutter, the way that the camera controls the shutter speed is to have a gap between two curtains that sweep across the frame. As the shutter speed gets smaller, the gap between the curtains gets smaller and smaller.

Your max. sync speed (aka the X-sync speed), is the fastest shutter speed where the entire sensor is exposed all at once. Once you go faster than that, part of the frame will be blocked off by the trailing curtain when the flash burst hits.

This is one of the reasons that it's sometimes worth blowing some extra money for an on-brand TTL-capable flash: the ability to do high-speed sync (the camera and flash blip out synchronized pulses of light as the curtain travels across the frame so that the entire frame is "covered" by the pulses).

[cold-chilli]

Thanks for your help. More stuff to learn I guess so I'll start with TTL and how to use it. Can TTL be used off camera utilising these:

4CH Wireless Radio Slave Strobe Flash Trigger PT04 AR02 on eBay (end time 23-Sep-09 03:17:31 BST)

I'm not 100% sure on using TTL so had better start learning.

[inkista]

Ok, I should also be persnickety and state that TTL doesn't always translate to high speed sync included, it's just does often enough, that it's a decent short hand way of specifying it, but if you're using vintage flash gear, you may want to do some research. The SB-24 won't do it for you, because it only speaks Nikon TTL, and the non-digital version at that--you'd need a relatively new Sony flash. TTL just means that the camera/flash talk to each other enough that the camera can automatically set the flash's power based on metering with a pre-flash. That's why you have to have on-brand gear to do it--there's no electronic standard for how this is accomplished, and everybody does it a slightly different way.

And, at this time, no radio triggers that cost under $200 for a unit are capable of doing TTL. The PT04s, like the Cactus V2s and V4s, Cybersyncs, and Radiopopper JrX units cannot do TTL or high-speed sync (with the exception of the JrX faking high-speed sync with studio monolights by extending the flash burst).

The only two right now that can are the RadioPopper PX units ($500 for a Tx/Rx set), and the TTL-capable PocketWizards ($420 for a Tx/Rx set: Flex-TT5 and Mini-TT1, which are only available for Canon, right now). In addition, both of these systems require that you have TTL-capable flashes as slaves, and in the case of the PX, a TTL-capable master as well (the PXs just take the on-brand infrared system signalling and bridge it over radio; they don't generate the master signals); this could be your pop-up flash; I'm not that familiar with Sony stuff, as I'm a Canon shooter.

However, using high-speed sync wireless, as long as you're in an indoors situation with line-of-sight, pretty much means using your brand-specific infrared signalling system.

[cold-chilli]

Thanks ever so much Inkista, your reply has cleared a fair few things up for me.

Thanks again, James.