550ex and Drebel behaviour

[swblackwood]

I have this combination and here's my dillemna. When using FEC whether seting it on the flash or via camera (with the hacked FW), I get range readings that are the opposoite of what they should be. With a Fec setting of -3, I get a range at the far end. With +3, I get the short end. I must add, however, that the flash fires correctly. It is just the flash range that is wrong. If I do other things that affect the range such as upping the ISO, the range behaves appropriately. I should also add that the prob;em predates the hack.

I have had the flash for far beyond the warranty, so I wouldn't bother having it fixed but I am curious as to whether others have had this experience. The 550ex predates the Drebel and was intended for the EOS film cameras so maybe some weird command is coming from the Drebel that causes the incorrect reading.

Thanks for reading.

[robertwgross]

I have this combination and here's my dillemna. When using FEC whether seting it on the flash or via camera (with the hacked FW), I get range readings that are the opposoite of what they should be. With a Fec setting of -3, I get a range at the far end. With +3, I get the short end. I must add, however, that the flash fires correctly. It is just the flash range that is wrong. If I do other things that affect the range such as upping the ISO, the range behaves appropriately. I should also add that the prob;em predates the hack.


Let's think about this, not make wild accusations.

When you set flash exposure compensation to 0, you are setting it "at the meter". When you set flash exposure compensation to +1, you are telling it that you need the flash and exposure to be brighter by a stop. In many cases, the flash pop can't get any brighter, so that means the effective range is going to have to reduce to make the exposure right. When you set the flash exposure compensation to -1, you are telling it that you need the flash and exposure to be dimmer by a stop. The effective range is going to increase somewhat. This is the way it is supposed to be, and it is the opposite of what you seem to expect.

So, go think this over and see if it makes sense now.

---Bob Gross---

[swblackwood]

Let's think about this, not make wild accusations.

When you set flash exposure compensation to 0, you are setting it "at the meter". When you set flash exposure compensation to +1, you are telling it that you need the flash and exposure to be brighter by a stop. In many cases, the flash pop can't get any brighter, so that means the effective range is going to have to reduce to make the exposure right. When you set the flash exposure compensation to -1, you are telling it that you need the flash and exposure to be dimmer by a stop. The effective range is going to increase somewhat. This is the way it is supposed to be, and it is the opposite of what you seem to expect.

So, go think this over and see if it makes sense now.

---Bob Gross---

That is not as it is explained in the manual and not how it behaves. When you set it to, sy, -3, the range is very close to the camera, which is why it might be good for a macro. However, the range indicator is showing readings 50 ft away. I believe that I have either a defective unit or the camrea is sending reverse information.

[robertwgross]

That is not as it is explained in the manual and not how it behaves. When you set it to, sy, -3, the range is very close to the camera, which is why it might be good for a macro. However, the range indicator is showing readings 50 ft away. I believe that I have either a defective unit or the camrea is sending reverse information.

This does not sound like the same question or the same description that you first posted, so I guess this needs clarification. You mention the range in one place and then the range indicator another place. I know only of the range indicator on the 550EX. What is very close and what is 50 feet?

Which manual, which page?

---Bob Gross---

[robertwgross]

The 550ex predates the Drebel and was intended for the EOS film cameras so maybe some weird command is coming from the Drebel that causes the incorrect reading.

Yes, the 550EX predates the Digital Rebel, but the one intended for EOS film cameras was probably the 540EZ, so we have not established that there was any weird command nor any incorrect reading.

---Bob Gross---

[PacAce]

I have this combination and here's my dillemna. When using FEC whether seting it on the flash or via camera (with the hacked FW), I get range readings that are the opposoite of what they should be. With a Fec setting of -3, I get a range at the far end. With +3, I get the short end. I must add, however, that the flash fires correctly. It is just the flash range that is wrong. If I do other things that affect the range such as upping the ISO, the range behaves appropriately. I should also add that the prob;em predates the hack.

I have had the flash for far beyond the warranty, so I wouldn't bother having it fixed but I am curious as to whether others have had this experience. The 550ex predates the Drebel and was intended for the EOS film cameras so maybe some weird command is coming from the Drebel that causes the incorrect reading.

Thanks for reading.

There's nothing wrong with your flash, just your understanding of how the flash should be behaving when using FEC. Go over Bob's explanation again and maybe it'll make more sense to you the second time around. :)

[swblackwood]

I guess I am not being clear. When the flash is operating normally, the range is something like 3.5 to 32 ft. At -3, the range is registering 8 - >60ft. AT +3, the range is registering 1- 12 ft. This, it seems to me is the opposite of what it should show.

[Jon]

Well, at +3 FEC, you're saying that you want it to give the subject +3 stops of light over what "normal" exposure would be. It won't be able to deliver that as far out. It's not the same as increasing the ISO 3 steps. An ISO increase tells the camera and flash that you need 3 stops less light for a correct exposure (the higher ISO is more sensitive to light), so corresponds to a FEC of -3.