Understanding Exposure

[KellyL]

Thank you very much for your honesty Glen. I appreciate your advice.

[KellyL]

Glenn, had I underexposed a half a stop, then I would have set my shutter speed to 160? Slower shutter speed lets more light in, so a shutter speed of 50 would have blown all highlights. A shutter speed of 160, as Jay did, would darken (?) the picture or the sky? Numbers going in the opposite direction of their function confuse me easily. It wasn't until I saw the F stop as a division problem that I could easily make sense of it.

[Crotographer]

The first choice I make is f stop. Whether adding or subtracting. I want to use f stop to help determine DOF. Shutter speed I leave dependent on my selection of f stop. Depending on what I am doing I leave shutter speed alone or determined by the formula of the particulars involved in the exposure I am shooting.

I only use shutter speed as a prime motivator for lack of light or capturing motion. Other than these two elements, I use f stop to deduct or add. It's tough to explain as they are used in combination. Suffice it to say that my primary concern is depth of field. A secondary concern is how much light I need for certain areas or motion, as stated before.

Depth of field is primary in making a statement. F stop gives you this. Shutter speed is a compliment to depth of field. I always set my lens for DOF. I use a tripod to help if the shutter speed required is slower than I can adequately hand hold.

I hope this helps. I can only type words.

[KellyL]

Glen, I am very familiar with the relationship between F Stop, shutter speed, ISO and DOF. Now, distance from subject and how it affects DOF I have yet to fully comprehend. I know the closer I am to the subject and the wider the aperture, the less the DOF. I will worry about that at another time.

I was thinking in the shower today...I get so many things stuck in my head...and I was realizing...I was pretty happy with the sunny 16 rule as long as the sun was behind my back. As soon as the sun was in front of me, I needed to add flash.

And I know this has been said before on this thread...sunny 16 is a starting place. I could have used any of the equivalent exposures if I wanted to affect the DOF.

16/100 = 32/50 = 11/200 = 8/400.....right?

I need to commit the "full stops" to memory. I believe someone on this thread listed full stops.

[Jason Hermann]

Originally Posted by KellyL

Glenn, had I underexposed a half a stop, then I would have set my shutter speed to 160? Slower shutter speed lets more light in, so a shutter speed of 50 would have blown all highlights. A shutter speed of 160, as Jay did, would darken (?) the picture or the sky? Numbers going in the opposite direction of their function confuse me easily. It wasn't until I saw the F stop as a division problem that I could easily make sense of it.

Kelly, Thanks for the props my friend Exposing for the sky was key. Thats all that mattered to me in my shot. I knew if the sky looked good I could possible get the shot I wanted. What I didn't know, was what the flash would do. That's what I'm trying to learn/ predict. If the flash didn't do what I was hoping, than my shot was just not meant to be. That was what I was thinking anyways

In my case the sky metered at f/11 1/200sec aimed right at the clouds. I lowed the shutter 1 setting which was 1/160sec (I believe that is 1 stop? I really don't know) I figured that would still offer a great sky and allow for jonny to look a little bit brighter so the flash would not have to work so hard.

I was shooting at about 6pm as you stated. That compared to 3pm makes a huge difference!! The sun has to go through so much more atmosphere at the angle I shot at vs your sun angle. Therefore I had less harsh light than you to work with. My shot was much easier to expose for based on the lighting than yours IMO.

Now, for your shot. I think that is a perfect example of not enough Dynamic range to get the exposure you wanted. Thats a scenario where you have to be like, My camera can't do it, so what can I do to make the best of it?? Underexpose and recover in post. Thats what I would have done anyway

Kirk is correct if the flash would have worked for you, but with no flash your screwed. The only option I can see is to underexpose and recover, or blow the highlights and have most of the subject look good.

On a slight side note, How far is your flash effective??

Crotographer, Great advice and thanks for sharing your thoughts!

Best,
Jay

[KellyL]

Jay...you left out one important piece of information. When you metered the clouds, did you use evaluative, center weighted, or spot metering? It would make a difference on your reading, it would seem.

So when you LOWER the shutter speed, you are actually letting in more light.

So if you metered for the clouds, that would put them smack dab in the middle of your zone ruler. By opening up the camera one stop, you moved the clouds one zone to the right. I am using "zone" very loosely. By doing so you are still preserving detail in the highlights and sacrificing in the shadows.

Now, as far as how much space is covered by the flash? Good question. I may be underestimating my flash unit. I still won't use that Metz flash. Adding three more dials to the mix right now is nothing short of a nightmare. Good grief, it only took how many blown exposures for me to constantly remember...ISO...ISO....ISO....because I would shoot at night, then go out the next day and forget to change the ISO. Thank goodness those days are behind me!

So...back to the flash. There is a table in the back of my flash book...I don't think I believe what I am reading. I can't recreate the table but it looks like this:

Coverage / distance (Coverage would be the lens focal lenghth, distance would be the flash.) Am I reading this correctly?

14mm/49.2f 24mm/91.9f 28mm/98.4f 35mm/118.1f 50mm/137.8f 70mm/164f 80mm/173.9f 105mm/190.3f

The top of the table reads Guide No. (ISO 100, in meters/feet)

SO...

If the lens is at 50mm then in normal flash I can expect the output to be 137 feet? That sounds perposterous!

[KellyL]

Jay, I am very thankful that you are taking this seriously, too. It makes me feel less foolish.

[Jason Hermann]

Kelly,
It was set to partial metering which I believe is the spot metering equivalent on my camera. And yes, by lowering the shutter it allowed MORE time for the light to get to the camera sensor.

I can't image your flash goes that far, but I would assume at full power it would at least go 25-35 feet and still be affective??

I'm happy to participate Kelly, I still have a lot to learn about exposure so sharing it on this thread reinforces what I learned by writing it down Taking notes is not my strong suit and never was in school. This thread is a perfect excuse to force me to take notes lol Plus you get the added benefit of helping people who still struggle with digital exposure's challenges.

Best,
Jay

[KellyL]

You are right Jay.

[KellyL]

Full increment f/stops:

1.4 2.0 2.8 4 5.6 8 11 16 22

Each increment halves/doubles the light. Jay, we need to memorize these. With our digital wands, we can more f/stops in tighter increments.

[jfrancho]

Originally Posted by Crotographer

Always feel free to deduct one half stop from your meters reading in a situation such as this. Afternoon sun is a curse to highlights. More than half a stop can get your shadows in trouble. Again, practice produces intuitiveness.

Originally Posted by Crotographer

The first choice I make is f stop

While we're in the midst of a technical discussion, I didn't want these two tidbits to get lost in the flurry of posts. Two points that make sense, the first being a tip that works, and the second represents just about all of how I make my pictures.

This thread continues to produce.

[KellyL]

I am very happy with the productiveness of this discussion. Glen's comments did not go unnoticed, and I am glad you reinforced them John. Bryan Peterson suggests underexposing 2/3 stop, so everybody is in the same ballpark with exposure. Slowly but surely I am coming around to a deeper understanding.

The second point is exactly what I was thinking in the shower this morning. On Saturday, I kept thinking, "But I don't WANT to use f/16..." Now why it didn't dawn on me in that moment that I could manipulate away, is beyond me. F/16 at 100 ISO 100 is the same as f/5.6 1/1000, is it not? The shutter speeds get me confused because there are so many variations. ISO is becoming more confusing now that I have the 30D. Crazy. ISO is in thirds.

A co-worker just handed me a copy of "Outdoor Photographer". Wouldn't you know...one of the cover stories is "Better Exposures for Digital". I am not alone. I have skimmed the article so far, and he describes the problem a lot, but doesn't offer many solutions. I'll give a fuller report later.

[jfrancho]

Slowly but surely I am coming around to a deeper understanding.

You learn like I do. It's like watching water boil for others sometimes... There is a thread where Mark recommended a printing technique, and I didn't get it; 40 posts later, he repeated his original statement, and I finally got it. What a maroon I am.

"But I don't WANT to use f/16..."

That's the ticket - figure out how you can not use f/16. This thought process is what led me to high speed sync, and ultimately, using a neutral density filter for brightly lit, outdoor pictures, like this (no flash is on the left, flash w/ND on the lens is right):

ISO is in thirds

Well, technically, on that camera it is, but I believe that they are simulated equivalents; actual changes in sensitivity are at full stops, or 100, 200, 400, 800, 1600, and 3200. Isn't nice that ISO measurements are more intuitive? 400 is twice as sensitive to light as 200? Just remember that if your camera is set to 1/3 stop increments, then three clicks is always a one stop adjustment.

I am not alone.

You most certainly aren't, but you've taken control of the situation, and asked the meaningful questions.

[cyclohexane]

Kelly, whatever you do, keep at it. You're doing a lot to further your knowledge.

Isn't nice that ISO measurements are more intuitive? 400 is twice as sensitive to light as 200?

I actually like the old DIN system, but I'm weird. ISO works great, and it (and ASA, sort of) did win out over DIN.

With our digital wands, we can more f/stops in tighter increments.

Actually, with my old, analog, aperture-ring controlled lenses I can set the aperture to anything I want in between the markings, but my cameras only offer full stop shutter speeds. Gain some, lose some. =)

[kgphoto]

Kelly,

As far as flash distance goes, my 200B will produce f:4.0 at 20 feet at a full power @ 100 ASA/ISO. If I add a telephoto reflector TO THE FLASH it will make f:8.0 with a narrower field of coverage that just happens to match my 250 mm Sonar lens. So it would have worked for your band person.

The key is to have the right tools for the job and know how to use them.

That is a professional.

That is why you pay them to do something you cannot do as well. Anybody can point a camera on auto and hope for the best the same as anybody can pound nails with a hammer. The difference is a pro know what hammer to use most efficiently and sometimes, that hammer is a nail gun.

Most pro flashes new have built in telelphoto settings or accessories available. If yours doesn't, time to upgrade. Then learn how to use it.

Shoot manual,not automatic. That is what is holding you back. You are not aware of what the settings are when you are in the moment. Auto it too easily fooled by changes, so you have to know when it is being fooled to adjust it. Since you are going to have to pay attention and think about the setting anyway, then just set them manually as well.

You are slowing down your understanding of what is "good or bad" by shooting on auto. Stop it! I can't make it any clearer. Yes, there will always be times that auto will work fine. Just as there will always be times when it won't. Don't be afraid and don't look for short cuts yet.

You can do it.

[Jason Hermann]

I really need to try and use manual exclusively as well. It's hard to justify though, when you have those nice little tools, like Av mode and such.

That being said it will force you/ me to learn. There is no option but to learn if manual mode is armed

Best,
Jay

[jfrancho]

I think we're speaking specifically to using manual when using a flash. It allows you to distinctly control the subject exposure and ambient exposure separately.

[Jason Hermann]

ahh. that makes perfect sense. Thats what I did because I knew If I recomposed the picture in Av mode, the camera would change for the current scene. Manual I had control so the only variable at that point was the what power to set the flash to. I already figured out what the ambient needs to be when I aimed at the sky and noted the shutter speed.

WOW, when you break it down like that it's almost seems easy in a way. Now to get the experience so I can predict what power the flash needs to be set to. Once I figure that out I should be all set

Best,
Jay

[kgphoto]

Actually, I recommend to use manual exposure all the time. Once you get it down so that you understand, then you can switch to auto if you want to take happy snaps and be lazy. However, you will find you get so fast using manual, that you will really regret using auto and getting a fouled up shot.

[Max@Home]

Originally Posted by Worm324

WOW, when you break it down like that it's almost seems easy in a way.

...it certainly ain't rocket science

...Once I figure that out I should be all set

...and then you buy a 'real' flashgun and the search begins again

...€0.02...

Kindest regards!

Max@Home