580ex working with a 135mm f/2 ???

[jsbedard]

I recently got the 580ex flash to complete my kit of Canon 5D +135mm f/2 L. The problem is that the flash focal range is from 24mm to 105mm. What is this sh** &???? How can i use it with my 135mm lens for portraits? The flash send too much light, the pictures are always blown up by an overflow of light. I tried to compensate -3 and use manual mode 1/128, but it is not great and very random results.

I tried find information on forums, but nothing about this topic! It seems I am the only dickhead having this problem. Can someone help me with this before I send back my 135mm lens to Canon please!

JS

[TMR Design]

Hi jsbedard,

I'm no expert on using a Speedlite flash for portraits but if you're using your 580EX to do studio work (portraits, headshots, etc.) then you want to NOT use ETTL but rather, switch to Manual and don't worry about the flash having a setting for the focal length of your lens. Then you would accurately measure the flash with a light meter to determine correct exposure. This way you are not using FEC but just dialing in the power level, adjustable in 1/3 stop increments.

[Curtis N]

The 105mm zoom setting on the flash will work fine for any focal length greater than 105mm. It covers a larger area than your lens, but there's no reason to be concerned about that.

There are several possibilities that could be causing the overexposure problem. Post a sample image with EXIF info and we'll go from there.

[René Damkot]

And off course there is the Flash Photography 101 (http://photography-on-the.net/forum/showthread.php?t=171657) from Curtis' sig...

[jsbedard]

Here are some sample pictures of my overexposure problem :

http://farm1.static.flickr.com/223/488984361_00e218c1e7_o.jpg

http://farm1.static.flickr.com/191/488984355_585ac3255a_o.jpg

http://farm1.static.flickr.com/191/488984347_f6d7574977_o.jpg

[René Damkot]

You were *way* to close in #3.
f/2 at ISO 3200 gives a *minimum* distance range for the 580EX of about 9 meters (!)
The flash simply isn't capable of shutting down fast enough...

The settings you used don't make too much sense IMO. Use a lower ISO, faster shutter, if your flash is main light.
If you want to use flash as fill, bounce it.
With the settings like you used them, you wouldn't have needed the flash.

I'd suggest you read a few of the links in Curtis' sig & re-read the flashes manual.

[jsbedard]

You see the speed? I cannot make the iso slower than 3200 else i will need let the shutter opened for 10 seconds, the room was quite dark. Look the EXIF infos please.

[jsbedard]

I was not too close, the lens is a 135mm. I was around 2m of distance, which is totally normal.

[Curtis N]

Too close for ISO 3200 and f/2.

If you want flash as your main light, switch to Manual mode on the camera, shutter speed somewhere between 1/125 and 1/200, aperture wherever you want, and ISO 400 or less.

If you want flash to be fill, bounce it like Rene' suggested and stay with the camera settings you were using.

[jsbedard]

Why ISO is making a difference. I was ISO 3200 right, but the shutter speed was 1/20 and the aperture f/2. It should be slow enough to record good light no?

[Curtis N]

It's about the flash unit's minimum output. ISO 3200 requires very little light for proper exposure. F/2 allows a lot of light through the lens. With this combination, the flash unit's minimum output is greater than what is required for proper exposure at that distance.

[René Damkot]

Like I said: Re-read the flashes manual. Page 11, point 3. :"Check that the subject is within the effective range displayed on the LCD panel". You are to close.
If you are using flash on ETTL, you can ignore the camera's light meter for subject exposure. If you take an exposure on ISO 100; 1/60; f/4, the background will be dark, but the subject will still be illuminated correctly by the flash.

The only reason to use high ISO / slow shutter with flash, is to expose the background with ambient in dark circumstances. It's often referred to 'dragging the shutter'.

Flash photography should be thought of as "two exposures in one" really: One(1) for ambient (background), and one(2) for flash (subject).

1: determined by aperture, shutterspeed and ISO
2: determined by aperture, ISO, and flash output (as set by ETTL), so effectively: ETTL rules this aspect.

[jsbedard]

Thanks people for the precision. (Flash photography should be thought of as "two exposures in one" really: One(1) for ambient (background), and one(2) for flash (subject)) = VERY GOOD way to explain it, i understood better with this, clearly.