Maybe a dumb question..

.. but i'll ask it anyway.
How can i check what minumum hss my camera have?
I read about flashes and some of them does not feature high speed sync above 1/250th.
But the reviewers keep mentioning that it has to do with the camera?

I want to buy the Sigma 610 DG ST, it does not feature HSS.. so, what are the limit on my 60D? And how can there be different limits like 1/160th?

Another question about HSS.. can't it be worked around? Let's say my camera limit it to 1/250th and i want to take photos on a bright day with the subject lit up... couldent i instead set the apeture to f/20 and shutter on 1/250th and still use a flash?
You freez most motion on 1/250th pretty well.. no?

You are confused I think.

The cameras sync speed is how fast of a shutter speed you can use with out the shutter obscuring the flash exposure. This is 1/250th on a 60d.

High speed sync, is a feature of certain flashes that allows it to fire many flash pulses in a short period of time, effectively allowing it to work at any shutter speed over the cameras normal sync speed.

For a visual of what is actually happening, see here http://www.exposuregui​de.com …flash/high-sync-flash.jpg

60D sync speed is 1/250s IRC. Should be plenty fast for freezing most action.

You could shoot at f20, but that's going to give you pretty bad diffraction softening. What you could do is use an ND filter on your lens to reduce the shutter speed. On a bright day it might be OK - but there's a risk it'll make the viewfinder quite dark and affect focussing.

Different cameras have different sync speeds due to the shutter design and size. As soon as the speed gets to the point that both curtains need to move together then you need a flash with HSS capability.

[Edit : my post and Steven's crossed in the ether. His jpg link explains it pretty well]

Yea, i'm pretty confused when it comes to flash and HSS.. not used to work with flashes.. it's a first time for everything though

If the flash does not support HSS, then the synch speed is what the camera dictates (1/250 for the 60D).

Your thinking is correct, but up to a point. Don't forget that the flash duration is much much smaller than the synch speed (say 1/5000 of a second). So, think of the flash firing as a 'package of light' you throw into the sensor through the aperture. The smaller the opening, the less light (from this 'package') will go through (as a matter of fact, every stop you increase, half the light goes through).

So yes, you can stop down to f20, but you would need a hell of a flash to light the scene through such a small aperture.

It's doubtful you'll need f/20 unless you're really trying to kill the ambient on a sunny day.
"Sunny 16" translates to 1/250 f/10 ISO 100. This will leave the shadow areas pretty dark. I normally shoot at f/8 or f/9 in the sun.

I rarely use HSS, but I have been known to screw on a polarizing filter, which will cut about 1 1/2 stops and allow me to open the aperture a little.

Looking a little better at the OP's original question, I could probably do a better job of answering than my first post...

Yes, it is down to the camera. Your sensor is 'hidden' behind a pair of sliding shutter curtains, and when you take a shot, the first curtain drops and reveals the whole sensor.

After the exposure time, the second curtain drops (to shield the sensor) then both curtains move together - still closed - back to their original position.

However, at some point, usually around 1/100 to 1/250s, the curtains can't move fast enough to completely open, wait for the exposure time, then close. So, instead, the first curtain opens a little, then the second curtain starts to move and follows the first across the frame. The end result is that every part of the frame is exposed for the right amount of time - e.g. 1/1000s - but it's been exposed as a rolling horizontal band that's swept down the frame.

As has been pointed out, a pulse from a flashgun is really short, so if you take an exposure of, say, 1/100s, the first curtain drops, at some point the flash fires, then 1/100s later the second curtain ends the exposure.

If you're over your camera's sync speed (faster than 1/250s for your 60D) then the flash pulse will happen at some point when your two shutter curtains are moving together across the frame. The end result is that only a portion of the frame gets light from the flash.

With a HSS capable flash, the flash instead emits a series of smaller pulses while the shutter curtains move, thus providing light for the whole exposure.

Hope that helps.

sploo wrote in post #15408694
60D sync speed is 1/250s IRC. Should be plenty fast for freezing most action.

This CAN be true but only if the flash is 2-3 stops above ambient. Easy to do in a poorly lit gym, not so easy to do in mid-day sun.

Tim S wrote in post #15410136
This CAN be true but only if the flash is 2-3 stops above ambient. Easy to do in a poorly lit gym, not so easy to do in mid-day sun.

Depends on how close you are to your subject.

Exif intact...broad daylight!

Holy crap! That is cool... looks like it is in the middle of the night.

Thanks for all the answeres and in-depth explanation (what makes POTN such a great place)..

So, since i rarely use a flash.. but it might come in handy on rare occasions, do you guys think Sigmas 610 DG ST will be ok for me?
I wont experiment with flash, i wont do studio work, i wont do much macro with flash, will mostly use it in poor lit conditions.. that is all.
it's around $120 here in Sweden.. the reviewers says it's a good flash.

I think the Sigma will work fine for you. My only caveat regarding aftermarket flash units is they sometimes aren't compatible with cameras that are introduced later. If you upgrade to a newer camera, you may need to buy a new flash to go with it. Conversely, every Canon EX flash unit still works as well on the newest cameras as it did on the old ones.

Have fun!

Curtis N wrote in post #15411805
I think the Sigma will work fine for you. My only caveat regarding aftermarket flash units is they sometimes aren't compatible with cameras that are introduced later. If you upgrade to a newer camera, you may need to buy a new flash to go with it. Conversely, every Canon EX flash unit still works as well on the newest cameras as it did on the old ones.

Have fun!

Yea, i need to check if there is a possibility to upgrade firmware for the flash.
I'm not swapping my 60D for another 2-3 years though.

Does the Sigma 610 DG ST work off camera with the 60D?

Ok, either i can't use google properly or there is NOT a single review/statement for the Sigma EF-610 DG ST if it works with 60D's wireless flash control.
The Super version can handle this.. but nowhere can i find if the ST version does..

To clarify, i want to be able to use the flash off-camera and still be able to remote it from the built-in flash. I tried this on the 430EX mk2 and i read that the Nissin di622 mk2 can handle this aswell.
Unfortunally i don't have the money for the 430 and the nissin is sold out in every store in town.

Anyone know?

I am no Sigma flash expert, but if I am reading their website correctly it looks like you have to have the Super version of this flash to have wireless capability.
EF-610 DG ST http://www.sigmaphoto.​com/shop/ef610-dg-st-sigma No mention of wireless TTL.

EF-610 DG Super http://www.sigmaphoto.​com/shop/ef610-dg-super-sigma

The fact that the DG-ST version only has 2 power levels when in manual mode would be enough to make me avoid this flash. You only have the choice of Full power and 1/16 power in manual.

If you are on a budget, look at the Yongnuo YN 565. There are lots of threads on here discussing that flash. They had some problems when they first came out but it seems that that is worked out now.

EDIT: I found this site that compares several flash models. It seems useful.
http://speedlights.net …or-canon-ettl-speedlites/

I agree with Dale. Sigma's ST models are for basic E-TTL flash on the hotshoe. No bells and whistles, which is why they're so affordable. If you want to use it off-camera or use manual flash, you'll want something else.