iphone x red eye with flash

Kurt Lang wrote:

The minimum shutter speed to avoid red eye is 1/125th of a second. 1/250th is preferred.

I've had high-end equipment over many years. Back In the day of flash bulbs, I would take flash shots at 1/1000 second (my cameras had an FP sync). Unfortunately, that's physically impossible with today's SLRs and electronic flash.

I would take flash shots at 1/1000 second (my cameras had an FP sync). Unfortunately, that's physically impossible with SLRs and electronic flash.

Ah, but you can! I knew my D800 has FP sync, but have always manually changed the shutter speed to 1/250th. Turns out, I don't need to do that. With a compatible flash (my SB-600 qualifies), all I have to do is change one setting in the camera's flash operation and it automatically uses a 1/250th or 1/320th shutter speed. Whichever one I feel like setting it to. From the manual.

Select 1/320s (Auto FP) or 1/250 s (Auto FP) for Custom Setting e1 (Flash sync speed, Page 299).

The D800 will drop back to 1/60th if I use the little popup flash.

We might be arguing semantics here but the SB-600 is not providing a true FP flash. FP bulbs are long-burning with (relatively) flat intensity curve. The flash sync trigger occurs immediately before the shutter starts to open. FP bulbs provide continuous illumination for about 1/60 second, covering any shutter speed 1/60 and above up to the maximum capability of the camera which, in those days, was commonly 1/1000 and occasionally 1/2000. Keep in mind that I'm going back fifty years.

FP flash with the D800 and SB-600 is similar but not identical. Long-burning electronic flash is not possible. What happens is that your SB-600 fires repeatedly and rapidly to simulate a single lengthy illumination. Because this is extremely inefficient AND the illumination is not truly continuous, Nikon has limited your sync speeds to 1/320 or 1/250. To the best of my knowledge, you can not shoot at 1/1000 and you also can not use FP mode at 1/125.

You've only proven you chose not to read anything other than "Nikon". Everything else applies directly to slow shutter speeds with a flash in low light. Doesn't matter if you're talking about digital or film cameras. Why you think an iPhone X should be exempt from this problem is anyone's guess. Other than, you simply choose not to believe a decades old fact.

We might be arguing semantics here but the SB-600 is not providing a true FP flash.

No, not semantics at all. I'd never looked into the difference before, but your explanation makes complete sense. A real bulb designed to slowly burn with continuous light, versus an electronic strobe that has to try and simulate that with very rapid pulses. That's likely the reason the camera will offer an FP sync speed no higher than 1/320.

For no reason other than I had never tried it before, I shot a low lit area about 20 feet away with the shutter speed at 1/320, 1/1000, 1/3200 and even 1/8000. All came out the same. The D800 and the dedicated SB-600 flash do a fantastic job syncing to each other. I'm sure helped to have a 1.4 50mm attached. Lots of lens. 🙂

You can't. Not within the phone. It's set up to be the same as any other inexpensive, easy to use camera. No fiddling with settings. Point - Shoot - Image.

A bit more info from the same site I got the italicized information above.

Because the iPhone's lens apertures are fixed (f/2.4 for the telephoto lens on the iPhone X, and f/1.8 for the wide-angle lens), your iPhone automatically tweaks ISO and shutter speed whenever you shoot an image with the Camera app to try and get you the best image possible. (If you use a third-party manual camera app, you'll be able to adjust these values manually.)

So, the iPhone X does have the ability to adjust shutter speed, but you normally have no control over it. I haven't looked into any of the manual control apps suggested by the site, as I underlined above. I would imagine they're a separate app that takes over control of the camera, rather than using the iOS supplied camera app. I can't say how well any of these would work since I've never tried one on my iPhone 6s, or have even looked one up on the App Store.

Up to you if you want to experiment to see if you can get better control over the camera. Particularly, forcing a higher shutter speed when using a flash.

Kurt Lang wrote:

For no reason other than I had never tried it before, I shot a low lit area about 20 feet away with the shutter speed at 1/320, 1/1000, 1/3200 and even 1/8000. All came out the same. The D800 and the dedicated SB-600 flash do a fantastic job syncing to each other. I'm sure helped to have a 1.4 50mm attached. Lots of lens.

Aaah... That's FP sync. I downloaded the D800 User Manual and the 1/250 and 1/320 FP settings apply only with the on-camera flash and non-compatible flash heads. The SB-600 IS a compatible flash head and you can get FP Flash at any shutter speed up to 1/8000 (as you've demonstrated).

The problem here relates to the nature of the shutter mechanism. One curtain opens the shutter and a second curtain closes the shutter. Up until maybe 40 years ago, the shutter curtains were fabric and they moved horizontally. Each curtain took nearly 1/60 second to traverse the required 36mm. That meant that with a shutter speed of faster than 1/60 second, the second curtain would begin closing the shutter before the first one had reached the other side. At these higher shutter speeds, there would be no instant in time when the shutter was fully open. Later cameras incorporated a metal shutter and the critical shutter speed was 1/125 second and even later ones moved the curtains vertically so that they needed to travel only 24mm and 1/250 became the critical speed.

Normal electronic flash is so brief that you can consider it to be instantaneous. Consequently, the flash MUST fire when the shutter is fully open. If the shutter speeds exceed the values stated in the previous paragraph, the shutter would NEVER be fully open. When I got my first electronic flash head some forty years ago (when the limit was 1/60), I carelessly set the shutter to rates of 1/500 and 1/1000 because I was used to FP bulbs. The photo was way too dark except for a properly exposed vertical band! Your D800 won't allow you to use REGULAR (X) electronic flash higher than 1/250 second.

Leaf shutters ALWAYS have an instant in time when the shutter is fully open and an electronic flash will fire at that time and this entire discussion it moot. On the other hand, leaf shutters are weak with non-flash shots because the center of the frame gets more exposure than the areas near the edges, as much as one stop difference.

Kurt Lang wrote:

I haven't looked into any of the manual control apps suggested by the site, as I underlined above.

The Adobe Lightroom app includes a camera control function with manual. However, I'm not too pleased with its automatic control. In dim light it has a tendency to use shutter speeds too long for hand-holding instead of tweaking the ISO and/or turning on the flash.

By the way, one MAJOR advantage to FP flash that many persons don't think about is fill-flash outdoors.

I do that a lot. Especially if the only good way to position the subject is with the sun behind them. Nothing worse than shots that are well lit overall, and the subject still look like they're indoors.

Please take me off this hacked thread. Please stop with the emails already. You win, I am done.

No one can remove you but yourself. Click the Following button at the top of this page.

How did you solve it? Inquiring minds want to know.

Do you have the iPhone X ? Or are you just giving us a photographer answer ?