Rebel t5i 18-55mm pop up flash issue

[ianlawrence]

Im a beginner and my problem is that my new t5i is not working anymore in manual or auto int mode . I test it in the dark room, in auto mode, the flash is firing but the image is dark. Any suggestions?

[Mykolas]

Hi ianlawrence!

Thank you for posting!

Do you have a sample image you can upload that we can take a look at?  This will greatly help us to determine why the images are so dark.  I know that the AUTO mode is not always the best mode for every shooting condition, so it could be normal that the images are not properly exposed.  What settings did you use in the Manual mode that gave you a dark image?

If this is a time sensitive-matter, additional support options are available at Contact Us.

[Bethy]

I am experiencing the very same issues, although it happens sporadically. In all automodes, as well as manual. Doesn't matter which lens I use, nor how close or distant I am from what I am trying to photograph. This just started happening.

[TCampbell]

Assuming that your flash is in E-TTL mode (because it could be in manual mode -- in which case none of what I'm about to write would apply.)...

Make sure you have not dialed in flash-exposure compensation.  In full "auto" mode you wont be able to do that (full auto mode limits the things you can change) but in creative modes (P, Av, Tv, or M) you can change it.  

Flash Exposure Compensation (FEC) allows you to tell the camera to fire the flash at either a lower or higher power than the computer calculates should be correct for the exposure.  1 "stop" a halving or doubling of the amount of power (obviously there is an upper limit to what the flash can provide so asking it to increase the FEC will be capped at either 3 stops or whenever the flash hits that upper power limit.)    3 stops of underexposure is half of half of half or 1/8th power.  That would cause a heavily underexposed image if the flash is being used as a "key" light.  I use FEC very commonly when shooting outdoors in the sun to use the falsh as a "fill" light.  I still want the sun to be the primary light source, but I want to use the flash to reduce the darkness of deep shadows.  When shooting outside in full sun, I typically set the FEC on my flash to -1 (which causes it to fire at half of the power that the computer would have otherwise used.)

ALSO... it's important to understand how E-TTL flash works...

1)  The camera "meters" the shot in evaluative mode and checks the lighting for each zone.

2)  The camera fires the pre-flash... at a very low power level (I think it's 1/32nd power by default) WHILE simultaneously re-metering the shot.

3)  The computer then compares each zone from 1 to the same zone in 2 to compare the difference in the "without" vs "with" light from the flash to see how much of an impact the flash had.  This helps it calculate how much power should be used for the shot.  Also... it's trained to watch for areas which fail to show much of a difference as well as areas which show too much of a difference.  E.g. if you were shooting a photograph of a subject who had a mirror in the background as well as a lamp next to them, then the lamp would appear to be about the same brightness in both metering tests (because it emits its own light) and the mirror would show a HUGE difference in both metering tests (because it is highly reflective.  The camera realizes they are both anomalies and is programmed not to be fooled by them.  It uses the zones that show a more typical difference.  Lastly... IF the flash is (a) on the camera and (b) pointed straight ahead (because a speedlite flash could be located off-camera or it could have it's head tilted away from the subject then the camera also uses the lens' focusing distance to subject to calculate flash power as well (both a and b must be true or the camera will not factor focus distance into the caluclation for flash power.)

4)  If FEC was set to any value other than 0, the computer will increase or reduce the amount of power the flash is using.  Additionally if you have mutiple flashes and set flash ratios, etc. these will also be factored in.

5)  Finally... the camera shutter opens and the flash fires at the pre-calculated power level.

All of these steps happen so quickly unless you were really watching closely you'd swear the flash tube only fired once.

The take-aways from this are:

1)  The FEC setting can cause the issue you are describing (it is the most likely reason for a functioning camera and flash to do this -- and would not be an indication of a problem or defecct.)

2)  E-TTL isn't a human brain.  It doesn't actually "know" what exposure to use.  It's firing some test flash and measuring reflections.  Due to the variable nature of subjects and reflections it is posible to trick the camera & flash.  

3)  You can always switch the flash to manual mode.  In manual mode it will fire only at the power level that you set and it will not perform any calculations or fire a pre-flash.  

If you are using the built-in pop-up flash, make sure you are not holding the camera in such a way that your hand or clothing are blocking the light from the flash... or that the camera strap is hanging in such a way that it's blocking the flash.

The intensity of all light sources drops off following a law of physics called the inverse-square law.  Each time the distance increasses by about 40% (1.41 -- technically the square root of 2 but you can just round that to 1.4 and be close enough) the amount of light from the flash will be halved (or each time the distace is doubled it will be 1/4 of the light vs the previous distance.)  The built-in pop-up flash is not particularly powerful (not anywhere near the power of an external speedlite such as the 430EX II or the 600EX-RT.)  The pop-up flash can provide enough light for subjects that are relatively close (at ISO 100 it's good for about 10 feet... maybe slightly more.) 

[RobertTheFat]

---

@TCampbell wrote:

Assuming that your flash is in E-TTL mode (because it could be in manual mode -- in which case none of what I'm about to write would apply.)...

[etc., etc.]

---

Tim's very detailed explanation is excellent, as usual. I'd just add one oversimplified, but useful, takeaway: E-TTL is pathalogically averse to blown highlights. If you're not careful, it's easy to create a situation in which only the very brightest object in the picture is properly exposed. Usually, the most effective workaround is to expose for the background and treat the flash as fill. There are times when even that trick is ineffective and you may have to switch to manual flash. But it works more often than you might think.

[TCampbell]

The built-in popup flash on the camera is NOT good for subjects at distance.  It is generally adequate for any subject within roughly 10'.  If you're shooting in a large room and your subject is far away, it's going to look like the flash didn't work even if it did work -- because the distance is too great.  

You can add an external speedlite which is considerably more powerful.

If your subject is close but you're still getting dark images then it is possible to put the flash into a mode where YOU see the flash fire even though it's technically "disabled".  The flash can be used to optically trigger remote flashes.  To do this, the camera communicates with the remote flash optically.  The on-camera flash technically fires a 'pre-flash' before the shutter is open.  This tells the remote flash what to do.  The remote flash will then fire when the shutter is open, but the on-camera flash will not fire.  This happens extremely fast -- you'd swear both flashes fired at the same time (even though technically they do not.)

I'm wondering if you have mistakening put the camera into that mode.  I do not have a T5i so I can't tell you where the setting is located in your camera.  The menu is usually labeled "Flash control" or "External speedlite control" depending on the model.  

Usually full automatic mode (the green [A] on the dial) over-rides nearly all settings.  The flash should work correctly in that mode even if it does not work in any other mode.  

[Bethy]

I doubt very seriously that this person was mistaken about which mode they were using. Because I am now having the exact same problem all of a sudden. Although it is sporadically, some photos actually come out, others are just completely black. Doesn't matter if I am in the standard automode, the creative automode, or even manual; it is still happening. And I would like to know what is causing it. As much money as this camera costs, it should work correctly. I haven't done anything differently, so I am not sure why it isn't working properly now, I have had it for a year.

[DempseyGT]

I'm having the same problem. Flash either doesn'f fire when the shutter snaps, or fires before the shutter snaps, resulting in dark, underlit images even when I use the CA mode to force the flash. Sporadically an image will come out OK, butthey are mostly dark.  Did you ever solve the problem?

[Bethy]

No, I never solved the problem. It is extremely frustrating. And all of the comments made prior to your post, after my initial comments, do not apply to the problem I am having. Because I haven't changed anything. Considering that changes can't be made at all when using the auto mode, obviously that isn't the problem. And I am not blocking the built-in flash with my hand, clothing, camera strap, or anything else for that matter. Like you, Dempsey, sporadically an image will come out all right. But most come out completely black. Sometimes I get a picture that is almost blacked out, but I can still sort of make out the image. Only for the next shot to come out just fine. So without changing any setting, without changing position, without changing my subject, I will get a few completely black frames, followed by an almost black photo, and then a perfectly captured picture all taken in rapid succession. And each time the built-in flash pops up and seems to fire, and yet I have a ton of black squares.

[RobertTheFat]

---

@Bethy wrote:
No, I never solved the problem. It is extremely frustrating. And all of the comments made prior to your post, after my initial comments, do not apply to the problem I am having. Because I haven't changed anything. Considering that changes can't be made at all when using the auto mode, obviously that isn't the problem. And I am not blocking the built-in flash with my hand, clothing, camera strap, or anything else for that matter. Like you, Dempsey, sporadically an image will come out all right. But most come out completely black. Sometimes I get a picture that is almost blacked out, but I can still sort of make out the image. Only for the next shot to come out just fine. So without changing any setting, without changing position, without changing my subject, I will get a few completely black frames, followed by an almost black photo, and then a perfectly captured picture all taken in rapid succession. And each time the built-in flash pops up and seems to fire, and yet I have a ton of black squares.

---

We've told you what the problem probably is, but you don't believe us. And since you haven't shown us any pictures or described your shooting conditions in any but the most general terms, you may be right for all we know. But if you are, then there's probably something wrong with your camera. If that's what you were waiting to hear, then I'm happy to oblige. But I think your frustration will continue until you either provide us with more information to go on or take/send the camera in for repair.