Sigma vs. Canon flash for XTi

nobody

I am in the process of shopping for a flash module for my XTi. I have it narrowed down to about 3 choices:

(1) Sigma Electronic Flash EF 530 DG Super (about $260 on amazon)

http://www.sigmaphoto.com/flashes/flashes_flashes_details.asp?id=3263&navigator=1


(2) Canon Speedlite 430EX II (about $240 on amazon)

http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=141&modelid=17302

disadvantage: does not appear to have autofocus auxillary light.


(3) Canon Speedlite 580EX II (about $405)

http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=141&modelid=14998

disadvantage: costs about $150 more than the other two


I will probably upgrade to a 40D camera in a year or so. I am leaning towards the Sigma flash because it appears to have everything I want and at a competitive price. Probably the most extreme thing I will use it for is indoor action photos of various forms of dancing in poorly lighted areas. For that, I believe the auxillary light for autofocus is critical. I have tried this already with the on-camera flash in manual mode, and in most cases, it is insufficient unless they are just the right distance from the camera. All the flashes above will adjust their lighting angle with a zoom lense, but the on-camera flash is really only suitable for a fixed focal length and/or distance from the camera.

Any thoughts on this? Thanks.

ziggy53

I have 2 of the Sigma EF 500 DG Super flashes and I like them very much. They are not quite as easy to use as the original Canon 580 EX but I haven't see the 580 EX II and I know some things have changed.

I use them professionally as well as for personal photography.

The Sigma implementation of the Canon E-TTL II is accurate and consistant.

The Sigmas do not accept an external battery source.

Tee Why

If you are looking for a flash for action stuff, you may want to look at the recycling times, as Canon's are much faster IIRC. Personally, unless you intend to shoot a lot of flash or use it for professional work, a Canon 430EX may be a good mix of features, performance, and price.

Scott_Quier

nobody wrote:

I am in the process of shopping for a flash module for my XTi. I have it narrowed down to about 3 choices:

(1) Sigma Electronic Flash EF 530 DG Super (about $260 on amazon)

http://www.sigmaphoto.com/flashes/flashes_flashes_details.asp?id=3263&navigator=1


(2) Canon Speedlite 430EX II (about $240 on amazon)

http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=141&modelid=17302

disadvantage: does not appear to have autofocus auxillary light.

It does, in fact, have "Ultra-bright 2-LED focus assist-beam compatible with all focus points of all EOS AF systems, up to 9-point AF " (quoted from B&H on-line catalog.

nobody wrote:

(3) Canon Speedlite 580EX II (about $405)

http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=141&modelid=14998

disadvantage: costs about $150 more than the other two


I will probably upgrade to a 40D camera in a year or so. I am leaning towards the Sigma flash because it appears to have everything I want and at a competitive price. Probably the most extreme thing I will use it for is indoor action photos of various forms of dancing in poorly lighted areas. For that, I believe the auxillary light for autofocus is critical. I have tried this already with the on-camera flash in manual mode, and in most cases, it is insufficient unless they are just the right distance from the camera. All the flashes above will adjust their lighting angle with a zoom lense, but the on-camera flash is really only suitable for a fixed focal length and/or distance from the camera.

Any thoughts on this? Thanks.

I infer from the tone of your post that $$ are one of the decision criteria. If so, then as nice as the 580EX II is I think you can get a better bang-for-the-buck ration from either of the other two flashes.

As already mentioned, the Sigma flash, when used at full power, is spec'ed to recycle at approx 4 seconds (if you use NiMH batteries) whereas the 430 is speced to recycle in about 2 seconds. Have you actually timed 2 seconds. When shooting action, that can be the difference between putting food on the table and not eating for a week. That only applies if you are shooting at full flash power - at anything less the re-cycle time really doesn't make that much of a difference.

I have the 580EX, the 580EX II and the Sigma 500 DG Super and, from a performance perspective, they are nearly identical (and I would suspect the 530 to be better than the 500). However, I KNOW the user interface on the 580 flashes is MUCH nicer than on the 500 DG as is the build quality.

My son (26 years old) has the 430EX flash and has actually used it to help me shoot a couple of weddings. He had not problems getting enough light out of the flash to cover the shots, the recycle time was not an issue, and the build quality was every bit as good as my 580EX. He's quite happy with his flash.

If you are buying for personal use (rather than professional) and given that the power difference between the 430 and the 530 is not very much and the build quality difference is significant, I think I would probably recommend the Canon unit.

pyry

I've heard that the length of the full power flash is around 1/200 seconds on the Sigma - which is longer than the cross-sync speed usually is. The Canons manage about 1/900. All three have flash durations in the sub-millisecond range at lower powers. This means, that the Sigma might not be able to stop movement properly at full power.

However, if you plan on using multiple flash setups, the Sigma is capable of running as an e-ttl master, if I remember correctly, and has an optical slave mode (that means triggering from other flashes going off). Of the two Canons mentioned you'd need the 580 for multiflash master and neither has the optical dummy mode.

ziggy53

pyry wrote:

I've heard that the length of the full power flash is around 1/200 seconds on the Sigma ...

The Sigma EF 500 DG Super is rated at around 1/700th at full power. I haven't specifically tested it but I have had no problems with its ability to stop motion at full power.

The Canon 580EX is rated at 1/833th at full power.

P.S. If the Sigma flashes had a duration of 1/200th at full power they might be very popular because that would mean they would not have to use FP mode on dSLRs. Unfortunately, that is not the case.

pyry

ziggy53 wrote:

The Sigma EF 500 DG Super is rated at around 1/700th at full power. I haven't specifically tested it but I have had no problems with its ability to stop motion at full power.

The Canon 580EX is rated at 1/833th at full power.

P.S. If the Sigma flashes had a duration of 1/200th at full power they might be very popular because that would mean they would not have to use FP mode on dSLRs. Unfortunately, that is not the case.

You do have a point there.

Edit: You would still need FP mode for power control at high shutter speeds, but I believe you that the full pop isn't as long as my friend had told me (possibly defective unit, I think).

nobody

Thanks for all the info. I bought the Canon Speedlite 430EX II and it arrived just last night. In a short time of experimenting with it and reading the instructions that came with it, I figured out how to do 2 things: (1) Use the flash in E-TTL mode as a means of eliminating shadows in the subject's face and such. This doesn't affect the camera exposure settings that much when the flash is switched on and off. For example, the aperture and ISO might stay the same, but adding the flash in ETTL mode seems to cut in half the exposure time when shooting in Av mode as I often do. (2) Shoot in full manual mode with both the flash and camera. That requires some trial and error and can be useful in certain situations, but not action shots.

Now, what I can't seem to figure out is how to use the flash to improve a situation of trying to do indoor action shots at ISO 1600, F/2.8, exposure time of 1/100 sec. Is there a way I could use the flash at a set power, say 1/4 of full power, set the aperture and ISO, and then let the camera choose the exposure time? If I could do that, I would surely get better settings (like ISO 400, exposure time 1/200 sec.). Or even if I could set the flash power, exposure time, and ISO and shoot in Tv mode and let the camera choose the aperture. If I go in E-TTL mode, all I'm going to get in that situation is slightly faster exposure time and less shadows under the eyes, rather than better all-around settings. I don't like shooting in ISO 1600 unless I absolutely have to. Any suggestions?

ziggy53

nobody wrote:

...

Now, what I can't seem to figure out is how to use the flash to improve a situation of trying to do indoor action shots at ISO 1600, F/2.8, exposure time of 1/100 sec. Is there a way I could use the flash at a set power, say 1/4 of full power, set the aperture and ISO, and then let the camera choose the exposure time? If I could do that, I would surely get better settings (like ISO 400, exposure time 1/200 sec.). Or even if I could set the flash power, exposure time, and ISO and shoot in Tv mode and let the camera choose the aperture. If I go in E-TTL mode, all I'm going to get in that situation is slightly faster exposure time and less shadows under the eyes, rather than better all-around settings. I don't like shooting in ISO 1600 unless I absolutely have to. Any suggestions?

It depends a lot on the distance to subject and the focal length of your lens as well as the amount of ambient light.

At ISO 100 your 430EXhas a guide number (GN) of 141 feet with a 105mm lens. It will act like it has a GN of 282 feet at ISO 400 and a GN of 564 feet at ISO 1600.

With a 24mm lens the GN is 82 feet (or so) at ISO 100.

With a 50mm lens, GN 110 ft./ISO 100.

Using the formula, Aperture/GN = Distance

At ISO 400, f2.8 and a 105mm lens you could reach 100 feet or so at full power. At 1/4 power (you will have to test to see if that is accurate or not) maybe you get 25 feet.

ISO 1600, f2.8 and 105mm and 1/4 power and you're at 50 feet or so.

Factor in the ambient light contribution and you should have your answer.

darryl

nobody wrote:

(2) Canon Speedlite 430EX II (about $240 on amazon)

http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=141&modelid=17302

disadvantage: does not appear to have autofocus auxillary light.

Funny, I can only find the 430EX (not II) for $240 on Amazon:
http://www.amazon.com/Canon-430EX-Speedlite-Flash-Cameras/dp/B000AO3L84

The 430EX II isn't even released yet and is listed for $330:
http://www.amazon.com/Canon-Speedlite-II-Digital-Cameras/dp/B001CCAISE/

There's a whole thread about whether it's worth it to wait for the "refresh":

http://forums.dpreview.com/forums/read.asp?forum=1019&message=28945971

Apparently the improvements are:

• improved metal foot and lever lock and the complete 40D flash menu compatibility
• 20% [faster] refresh

Sucks for me because I have an Amazon gift cert + AT&T rebate card burning a hole in my pocket, and I need to take some portraits for my son's pre-school the first week of September, so I want to order soon.

I too have an XTi and in doing some testing the other day I found that the on-camera flash was taking *forever* to refresh, hence my need or an external flash. It's weird, but it almost feels like refreshes slower my original Rebel. Alas, I can't test that since that camera was stolen last year. :-{

nobody

My bad on the model number. What I actually have is the 430 EX.

Here's an idea that comes to mind: shoot in ETTL mode with the camera in Aperture priority at f/2.8 (or whatever is the largest), but add to whatever the flash module does (+2/3), then do just the opposite on the camera exposure (-2/3). Anybody tried that?

The difficult thing about shooting moving performers in manual mode is the inverse square law. Realistically, I might be dealing with people maybe 10 - 30 feet away, and that's a factor of 9 difference in luminosity, but if I am zooming in and out, then some of that is going to be compensated for by focusing of the flash to match the lense. I suppose that if I am composing a shot the same at 28 mm as at 70 mm, such as having the same person fill the frame in the same manner, then it's not going to affect my exposure. But if I move from a group of people at 20 feet to an individual at 20 feet, it will affect the exposure -- the individual will get more light because the focal length will be longer and the angle of view/flash will be narrower.