FF versus crop fireworks

I always had great luck shooting fireworks with my T2i, 60D, and 7D. Always used bulb mode, f/8, and ISO 100. 18-55 kit, 15-85, and 24-105 lenses.
Last year I got the 5D3 and found fireworks photos, from the exact same locations I had shot in the past, to be way underexposed with the 5D3. I had to switch to f/5.6 and ISO 400-800 (still using bulb mode). with the 24-105 lens.

Anyone have any thoughts on this? It doesn't make any sense to me. It's weird because everything I've ever read about fireworks says f/8 to f/16, ISO 100. Including a recent Adorama tutorial using a Canon 6D. f/8, ISO 100 was the ticket with my crop bodies, but not with my 5D3.

My 5D3 meters and exposes very similarly to my 7D in all situations except fireworks. I can take my 5D3 and 7D out in daylight and shoot the exact same settings for aperture, shutter speed, and ISO, and get extremely close results, as far as the overall exposure. I don't understand why I see a 2-4 stop difference with fireworks photos.

Do you have a couple of examples, one from each that you could share? There won't be anything inherent with the different cameras, as you point out, in any other more normal situation, they expose nearly identically. So it is either your exposure timesm or the fireworks were less intense than prior years, or poor contrast of the fireworks to the background, or something else along those lines, if I had to guess.

If those are the settings I am to use during fireworks, I really need to change how I do them. I guess it makes sense to lower the ISO to lower the shutter to get the trails and bursts in more glory, but the settings I used at Disney were way, way off.

TeamSpeed wrote in post #16067151
Do you have a couple of examples, one from each that you could share? There won't be anything inherent with the different cameras, as you point out, in any other more normal situation, they expose nearly identically. So it is either your exposure timesm or the fireworks were less intense than prior years, or poor contrast of the fireworks to the background, or something else along those lines, if I had to guess.

If those are the settings I am to use during fireworks, I really need to change how I do them. I guess it makes sense to lower the ISO to lower the shutter to get the trails and bursts in more glory, but the settings I used at Disney were way, way off.

Thanks for the reply. I'll dig up some examples the first chance I get (if I kept any of the underexposed 5D3 shots).

I had someone over on DPR say that they experience the exact same difference when shooting fireworks with the 5D3 versus a crop body.

Same AOV on both? Did the other person change their focal length to fill the frame equal to what the APS-C was showing? I could just wait for your posted examples, I guess, that would obviously answer the question.

KatManDEW wrote in post #16067285
Thanks for the reply. I'll dig up some examples the first chance I get (if I kept any of the underexposed 5D3 shots).

I had someone over on DPR say that they experience the exact same difference when shooting fireworks with the 5D3 versus a crop body.

It sounds to me like the 5D3 somehow isn't set up for fully manual exposure control.

Look up Tom Bricker. He's got a lot of knowledge when it comes to shooting fireworks and has done some really nice work with neutral density filters as well.

For these I used a "bulb" exposure, ISO100, F11. Live view-open shutter when mortar launch "whumpfh!" is heard, close shutter when burst dissipates.:

IMAGE LINK: http://anscochrome.zen​folio.com/p61809639/e3​edbe499

IMAGE LINK: http://anscochrome.zen​folio.com/p61809639/e3​0f58548