Saturday, January 30, 2010

Post 200

Light Description began a little more than three years ago; this is post number 200. Nothing particularly surprising in this post except the realization of averaging more than one post per week.

Taking a quick look at the Labels (left hand side of the display), most of the past posts have centered around learning to use the Canon G9 and/or flash. I still have and use the G9 regularly but probably will place more emphasis on the 7D during 2010. Flash is still intriguing to me and I have much to learn about it.

More to come in 2010 …


Friday, January 15, 2010

7D Sync Speed

Inspired by the Strobist, I checked my 7D to be certain of the sync speed when using flash. According to the 7D manual (pages 111 and 207), the maximum sync speed is 1/250 second. That is, because the 7D uses a mechanical shutter with all its accompanying timings, 1/250 second is the fastest shutter speed that can be used with flash. For the most part, this is the case with my own 7D but there are some variations.

My G9 with its electronic shutter could be used up to about 1/2500 second sync speed provided it did not know much about the flash that was attached. To take advantage of this odd behavior, I often used a Nikon SB-28 with the G9.

Before going too much further, yes, I am aware that the Canon flash system can operate in “High Speed” mode at shutter speeds faster than 1/250 second. However, High Speed mode uses pulses of light and the net lighting power is significantly reduced. Yes, High Speed flash mode works and is useful but the name of today’s game is syncing the 7D to that single burst of light when the camera is in normal flash mode.

The first clue to 7D flash sync occurs when using the built-in popup flash. There’s no way to set a shutter speed above 1/250 second. Also, there’s no High Speed mode for the popup flash. On the more positive side, at 1/250 second, the light appeared to be fully distributed over the shutter. Well, at least that experiment was easy.

Next, I tried a Canon 580EX, 420EX and 380EX. All acted similarly with respect to sync speed. The 1/250 second shutter speed combined with flash produced even lighting but faster apparent shutter speeds reverted to 1/250 unless the flash was placed in High Speed mode. I even tried the 580EX in full manual mode with the same results: 1/250 second is the fastest available shutter speed.

Time to try the Nikon SB-28. It syncs at 1/320 second! At 1/400 second there was a dark edge at the bottom of the image. About half the frame was dark at 1/800 second.

What about wireless? My cheap Cactus wireless triggers at 1/500 second on my G9 and, on a good day, even 1/640. Those same units are limited to 1/200 second on the Nikon SB-28 and Vivitar 285HV when used with the 7D.

I’ve been using the 7D popup flash to trigger the 580EX and really like this combination; however, the maximum sync speed is 1/250 second because the popup cannot operate in High Speed mode.

So the 1/250 second limitation is basically true. Oh well, if necessary, I still have the G9.

Saturday, January 9, 2010


I’m learning to use the AF-ON button on my 7D. Well, perhaps learning to use is not quite the best wording. AF-ON is, after all, just a button. I can already press it but I’m not in the habit of doing so. My habit is to press the shutter release button halfway, hesitate and then complete the press.

To take a picture, you point the camera at the subject and press the button – right? George Eastman built his company around the motto “You press the button, we do the rest”. More recent is the ongoing joke slogan about PHD cameras (“Push Here Dummy”).

The shutter button on many (most?) modern cameras actually has two “stopping points” or triggering positions. The first position is about halfway down. You can feel this first position by pressing the shutter button lightly and slowly. With a little practice, you can quickly get a feel for the effort and distance and the half-pressed button then comes quickly and naturally. The second position is the actual stopping point and is at the bottom of the shutter button stroke or press. The half-press has been my habit for a long time. It was especially useful with the G3 and G9 because those cameras had a very noticeable shutter lag unless the half-press technique was used. In addition to reducing shutter lag, the half-press was especially useful in the “focus, recompose, shoot” technique that I almost always use.

In addition to the two position shutter button, the 7D also has the AF-ON button. This button acts like the half-pressed shutter button. So what? Why use AF-ON ?

In addition to focusing, the AF-ON button locks focus as long as the button is held down. This means that I can focus, recompose, shoot, recompose, shoot, shoot, shoot, recompose, shoot, etc., etc. There’s no need to refocus as long as I remember to hold down the button. This is especially useful in portrait shooting. I’m no longer waving the camera around as I continually focus, recompose and shoot.

A good feature, AF-ON .

Monday, January 4, 2010

Top 3

The votes are in (courtesy of SmugMug statistics -- not visible publicly) and the most popular of my Top Ten is "Plantation Bedroom". In this case, most popular is awarded based on my eyeball judgement of the number of views with emphasis on views of large image sizes and the amount of bandwidth used in viewing. Plantation Bedroom is the winner by nearly a 3:1 margin. It was one of my early attempts at HDR and is derived from 7 images (sometimes I say 9 -- I've forgotten but it was more than 5) from the 20D.

Second place goes to "'Round the Campfire" which still makes me smile every time I see it. Another 20D shot, this one was carefully planned but still required a bit of cloning and layering multiple shots. I've even made a Blurb book of my Swiss Army Knives.

... and in third place we have the aptly entitled "Bike on Beach". This one was made with medium format twin lens reflex (TLR) film camera.

The other 7 pictures received nearly equal attention. At this time, I'm not replacing any of them but I am tempted to do so.