Question about lens aperture

[Bob Hartig]

I've just started working with the fully manual mode on my Rebel XTi. In fact, I took a class on it tonight and feel excited that I'm finally onto the solution for some of the frustrations I've experienced, not to mention the threshhold of discovering what my camera is really capable of.

Now for my question, addressed to those of you who shoot primarily in manual mode: Where do you normally set your aperture when shooting in a storm environment? Do you adjust to the center of your meter, or do you stop down?

The storms of May 22 and 23 were extremely dark, and I blew some great photos because my camera literally would not take pictures for me in auto mode. I'm curious what settings people were using. If any of you were in the string of vehicles east of Oberlin, KS, and got decent shots of the large tornado that crossed the road nearby, I'd be particularly interested to hear from you. I really screwed up that opportunity, and would welcome feedback for next time.

 

[John Wetter]

On the 22nd, I shot around f/5.6 and 1/50 of a second. Everything was either tripoded or at least monopodded though. Some were at 1/10 of a second. Many auto settings won't let it go that slow of a shutter speed.

-John

 

[Darren Addy]

This book comes highly recommended: Understanding Exposure: How to Shoot Great Photographs with a Film or Digital Camera

 

[Cris Schroeder]

Bob,

Depending on how dark it is, I'll shoot around f/5.6 using my 17-40L in aperture-priority mode. As it gets darker and the shutter speed drops, I'll start bumping up the ISO until I hit 400 or so. At that point I'll go back to full-open (f/4 in my case). If I'm shooting from a tripod I'll leave the aperture at f/5.6 or f/8 and drop the shutter speed as required.

Your question about centering the meter or stopping down is fairly easy. Set the display on your XTi for the tri-color histogram. Shoot an image, check for clipping on the LCD, then use the EV button to increase or decrease exposure as required (if shooting fully manual, then increase or decrease the exposure as required). FYI, I've found that the XTi tends to snug the histogram to the left (dark) side. Most of the time I can shoot 2/3 to 1 full stop over the metered setting without blowing the highlights.

The histogram is your friend!

 

[Darren Addy]

Just to follow up on Cris' point:
Understanding Histograms. Luminous Landscape is a great site to get you up to speed on concepts.

Don't know a lot about other cameras, but my K200D can be set to "blink" any clipped highlight or shadow areas at you on the LCD making them terribly obvious.

 

[Bob Hartig]

Thanks for the input, everyone. This is all very helpful. I checked out the tutorial on the histogram. Looks like that's the next feature I need to get better acquainted with. Darren, "Luminous Landscape" is great! I've bookmarked it.

Next time I'm in a very dark storm situation, I think I'll have a much better idea of how to handle it.

 

[Greg Campbell]

If you're the bookish type, tromp down to the library and rent The Negative, written by "that Adams guy." Although written in the film age, the concepts explained (exposure latitude, 'place' and 'fall,' contrast adjustment, pre-visualization, etc.) are still real and relevant. The material is coverid in some depth, but is written in an accessible, plain-English manner.

http://www.amazon.com/gp/product/0821221868/

The first book of his trilogy, The Camera, is recommended.


FWIW, I've always preferred shooting in aperture priority, using the exposure compensation buttons to tweak the density. If your camera doesn't have readily available exp-comp controls (is there a custom control option that allows you to slave exp-comp to a control whee?), you might be achieve this by shooting in manual mode, and 'needle matching' the exposure by eye, adding or subtracting a stop or two as needed. Is this what you've been trying?

 

[Doug Raflik]

I never use the histogram. You have a screen right in front of you that shows the picture. Use it. You need to learn how ISO, aperture, and shutter speeds alter your final picture and then adjust those as needed. Take a quick picture... if its too dark, adjust the shutter speed, if you are already shooting too slow for a moving object or hand held, adjust the aperture instead. If thats already stopped down as wide as allowed, then up the ISO. The ISO is always last for me, because that brings in grainy looking images if not careful.

This was shot May 23rd. ISO 500, f/3.5 at 1/50 second. Hope this helped.

Doug Raflik

 

[Mike Hollingshead]

I never use the histogram. You have a screen right in front of you that shows the picture. Use it.

I'd trust the histogram WAY before I'd trust what I can see on the LCD...IF...I can even see the LCD. Histograms can't lie, brightness settings on LCDs can. I have some super underexposed auroras from 2004 thanks to trusting/using my lcd.

The histogram is always easier to see and know where you are at with exposure than the LCD.

 

[Ryan McGinnis]

I'd trust the histogram WAY before I'd trust what I can see on the LCD...IF...I can even see the LCD. Histograms can't lie, brightness settings on LCDs can. I have some super underexposed auroras from 2004 thanks to trusting/using my lcd.

The histogram is always easier to see and know where you are at with exposure than the LCD.

Ditto. The histogram will never lie to you -- the LCD on my 30D is almost always too bright.

BTW, that's an awesome photo, Doug! The symmetry between the ground and the sky is uncanny.

 

[John Wetter]

I'd trust the histogram WAY before I'd trust what I can see on the LCD...IF...I can even see the LCD. Histograms can't lie, brightness settings on LCDs can. I have some super underexposed auroras from 2004 thanks to trusting/using my lcd.

The histogram is always easier to see and know where you are at with exposure than the LCD.

Couldn't agree more. I always shoot with the four-panel on my camera. The picture and then the three color histograms.

 

[Mike Hollingshead]

Couldn't agree more. I always shoot with the four-panel on my camera. The picture and then the three color histograms.

Yeah it's worth noting, many of the older LCD histograms only have one. Turns out they used the green channel for this, since it's the highest weighted color, since our eyes detect green the most or something. So if you shot something like a field of red flowers, or a red sky, the histogram may show it's not blown out, when in fact it very well could be and you are clipping reds. I think my rebel XT only has the one histogram like that.

 

[Gene Moore]

On May 22/23 it was dark especially later in the day. Not only low bases but thick anvil canopies shutting out most of the light. I shot my tornadoes about F 2.0 @ 125/sec 200 ISO.

Doug R....very nice shot, Quinter I south of the Interstate? Lets see more!!

 

[Cris Schroeder]

From Greg Campbell:

If you're the bookish type, tromp down to the library and rent The Negative, written by "that Adams guy."

I wholeheartedly agree. I picked up "The Camera", "The Negative", and "The Print" a while back. I shoot and develop B&W film, but was surprised at how relevant the books are to digital photography. Ansel's Zone System was based on getting the maximum information on the negative...kind of a 1940's version of "shooting to the right" on the histogram.

FWIW, I've always preferred shooting in aperture priority, using the exposure compensation buttons to tweak the density. If your camera doesn't have readily available exp-comp controls (is there a custom control option that allows you to slave exp-comp to a control whee?)

That is my preference, as well. The XTi has an exposure compensation button. Just hold it down and spin the wheel for +/- two stops of compensation. My XTi tends to shoot dark so I regularly bump it up a stop.