Auto Focus vs AF Selection on Canon 20D?

WolfOnDigital

Question for you?

I was using auto focus with my Canon 20D.
I decided to actually use the multi controller to select the AF Focus point I wanted.

I was shooting a model on location. I framed my image scrolled thru the focus points and selected one. When I looked at the shoot at the end of the day it seems the focus was not selected correctly?

Did I miss something here?
When the focus point you choose is lit up in the viewfinder does that mean you just shoot? Or do you like I did hit the AE Lock and then shoot?
I am thinking that by hitting the AE Lock after I chose my AF point I wanted defeated the purpose of me choosing?


Suggestions?

If I have to post an image or two I will try and do that.
Thought maybe some of you couldreally help run me thru the AF choice mode and see what I missed.
I had no problem focusing with auto focus before. The only reason I switched was it seemed I would have dead on control of each image.
I try and focus on the models eyes / face for the best focus point.

Or should i just go back to Auto Focus and lock in with AE Lock and then recompose?


Thanks in advance.
I have another shoot coming up and do not want to blow focus here.
I am trying to really lock down and master my 20D once and for all! lol

Jeff

Candid Arts

What you should be doing, is selecting the area of the picture that you want the AE lock to lock onto (I'm guessing a back lit sky or something then are using fill flash to light the model?), once your aperture and shutterspeed are set to the exposure you want, then re-compose, select the focus point you want, halfway press to lock focus, and shoot. I think that is what you're trying to do. What it sounds like you did was compose shot, focus where you wanted focus, re-composed to set your AE lock, went back to your first composition and shot. But even then, you'd have to half press to focus lock on the point you selected and shoot.

Some sample photos with exactly where your focus point was, all the EXIF info would greatly help.

WolfOnDigital

Actually....
Actually you jogged something in me here...:)
I was at the time of the shoot and in my post here confusing AE lock with Focus!
Stupid me...lol
AE is of course exposure lock!
So putting aside AE lock for the moment you are saying IN REGARDS TO FOCUS:

I can compose my shot, then select my AF (not AE) point and then shoot?

Jeff

Candid Arts wrote:

What you should be doing, is selecting the area of the picture that you want the AE lock to lock onto (I'm guessing a back lit sky or something then are using fill flash to light the model?), once your aperture and shutterspeed are set to the exposure you want, then re-compose, select the focus point you want, halfway press to lock focus, and shoot. I think that is what you're trying to do. What it sounds like you did was compose shot, focus where you wanted focus, re-composed to set your AE lock, went back to your first composition and shot. But even then, you'd have to half press to focus lock on the point you selected and shoot.

Some sample photos with exactly where your focus point was, all the EXIF info would greatly help.

Candid Arts

WolfOnDigital wrote:

Actually you jogged something in me here...:)
I was at the time of the shoot and in my post here confusing AE lock with Focus!
Stupid me...lol
AE is of course exposure lock!
So putting aside AE lock for the moment you are saying IN REGARDS TO FOCUS:

I can compose my shot, then select my AF (not AE) point and then shoot?

Jeff

Yes. Make sure your lens is on AF so it actually auto focuses to the point you select. Other than that you got it.

pathfinder

The AF system on the 20D has a strong preference for the closest significant line in the frame, strongly favors high contrast straight lines over softer, less contrasty lines. For example, when shooting someone wearing glasses, one must be VERY careful and place their AF point precisely over the pupil or the cornea, or the AF system will preferentially focus on the spectacle frame.

I use my 20D from time to time, and I have the same experience. I call this "herding the AF points' to keep the camera focused where I choose, not where the camera chooses. I do this by using a solitary AF point, and keeping recomposing to an absolute minimum after focus lock has been captured.

The AF system on the 1 series cameras seems to be much better at choosing what I choose.

ziggy53

pathfinder wrote:

... The AF system on the 1 series cameras seems to be much better at choosing what I choose.

WolfOnDigital

Thanks
Thanks for all the feedback


I'll get it yet.
It isn't that I do not understand photography since I taught it for many years it's just that I am still getting comfortable with the switch to digital and learning how my Canon 20D behaves. lol


I also noticed after checking the shot info on my images that some of my focus issues were due to slow shutter speeds such as 1/15 and 1/8 of a second. I was using my 24-70 Canon 2.8 L and I should have paid attention and realized you can't hand hold a lens of that weight and size at that slow of a shutter speed/s.
Shortly I will get into of the habit of relaxing more when shooting with the 20D and paying attention to the info in the viewefinder and the focus and the composition.
Had no problems in the older days with my match needle Canon FTB.

But I WILL get it!

When shooting a Model:

AV mode
Evaluative Metering, maybe spot metering at times
Shutter speeds no slower then 1/30 for optimal hand held focused images
ISO 100 to 200 for optimal quality (Higher ISO in lower light)
AF Focus Selection with minimum Recompose
A shot or two with 1/2- 1 stop under or 1/2 - 1 stop over to cover myself
And MAYBE finally switch to shooting in RAW or Raw plus fine jpg

I think the above combination of items will do fine.

What do you think?

Jeff

WolfOnDigital

Also a question of metering off of the face...
Does anyone have any tips on metering off of the face of a model?

I was told you can take the evaluative reading off of the face of the model by walking up and framing the model to fill the frame of the lens take your reading and then lock the exposure.
Hold the exposure and back up frame your show and select focus point and you are good to go.
I tried it today with some practice shots and it seemd to work fine.
Do you use spot metering at that point and move in and meter off of the face or stay with evaluative? or does it matter since you are metering off of the face and locking the exposure?

ziggy53

Jeff,

You "need" to shoot RAW. No question about it, really.

Use an 18 percent gray card at the model's location and meter off of that for best exposure. Use a calibrated white target for white balance and do a test anytime the light changes or you change locations.

Develop a RAW workflow that includes using the white target in the image to set your starting point for white balance.

Work on lighting the subject and choosing an appropriate exposure for the situation which includes both subject movement and camera shake. Once you gain control over lighting, use manual exposure for best results, especially if you used the gray card to establish your exposure.

Alternately, you can use an exposure meter to gauge proper exposure but be sure to calibrate the meter to your camera before trusting the results. Either reflective or incident meter will work with the appropriate technique.

pathfinder

WolfOnDigital wrote:

Thanks for all the feedback


I'll get it yet.
It isn't that I do not understand photography since I taught it for many years it's just that I am still getting comfortable with the switch to digital and learning how my Canon 20D behaves. lol

Shooting a 20D is not like shooting an F-1 Canon or a Nikon F-5. The AF system on the 20D does work, and used with some finesse will do as well or better than manual focusing ( Now this is my opinion, not a fact that everyone will agree with so don't you manual focusers start a flame war here ) But the AF system on the 10D and the 20D was not the smartest sets of algorithms around, so as I said, the shooter needs to be very precise and meticulous with it or it will find something nearer and sharper and focus on it instead of a models eyes or nose or mouth. This really has nothing to do with your skills as a photographer - I think of it more like driving a new to you manual transmission. You have to figure out just where the clutch begins to engage, even if you are Mario Andretti.

I also noticed after checking the shot info on my images that some of my focus issues were due to slow shutter speeds such as 1/15 and 1/8 of a second. I was using my 24-70 Canon 2.8 L and I should have paid attention and realized you can't hand hold a lens of that weight and size at that slow of a shutter speed/s.
Shortly I will get into of the habit of relaxing more when shooting with the 20D and paying attention to the info in the viewefinder and the focus and the composition.
Had no problems in the older days with my match needle Canon FTB.

But I WILL get it!

It won't take long at all - digital offers such immediate feed back that the learning ( or relearning ) curve is quite short. One word of warning, in my own experience, I find the image on the camera's LCD to be a very poor method of evaluation of how well focused I am. May it is just me, but I really find how well my focus has been when I see the images large on my 30 inch monitor. I think this is why many very successful pros tend to shoot tethered. There used to be a good video of Greg Gorman shooting in his studio in southern California with a large 24 in monitor to see the images on screen as they were captured.

When shooting a Model:

AV mode
Evaluative Metering, maybe spot metering at times
Shutter speeds no slower then 1/30 for optimal hand held focused images
ISO 100 to 200 for optimal quality (Higher ISO in lower light)
AF Focus Selection with minimum Recompose
A shot or two with 1/2- 1 stop under or 1/2 - 1 stop over to cover myself
And MAYBE finally switch to shooting in RAW or Raw plus fine jpg

I think the above combination of items will do fine.

What do you think?

Jeff

Jeff, I use Av mode much of the time when shooting, but I make a point of keeping an eye on what the shutter speed is doing, because I may need to change aperture or ISO if the shutter speed is not appropriate to the task at hand. I like to do at least one shot in manual mode so I know what the basic exposure should be near.

When shooting Av with a Canon flash, bear in mind the assumption is that you want to get the proper exposure of the background from the ambient lighting, and you CAN and sooner or later will, get shutter speeds of 1/2 sec or 1/10th seconds if the sun is down. For shooting ETTL in Av mode, you need to remember that a tripod MAY be necessary.

I shoot in Evaluative mode routinely, but some folks prefer center weighted. The 20D does not offer true spot metering. It does have Partial metering and and Center Weighted averaging metering.

Shooting in Manual mode on the camera and ETTL on your ESO system lets you control the ambient exposure of your background by your choice of aperture and shutter speed, and the EOS flash will light up your subject with the correct exposure.

I agree with Ziggy, an incident meter reading, or a reading off of a grey card will get you the most accurate exposure reading. I do agree that is you read off the face it will be close for most Caucasians, but you will find significant variations when you shoot folks with lighter or darker complexions than average Europeans. Some folks meter off the palm of their hand and add one stop of light to the reading.

WHen using a reflected light meter, what you meter off does not matter really if it is what you always meter off and then add the correct correction factor to that reading, because a reflected meter expects to see an 18% grey card.

If you meter off a grey card or use an incident hand held meter ( I use a Sekonic L-358 as it meters and triggers my flashes as well ) and shoot in RAW, I doubt you will need to shoot over and under exposures, unless you are doing so for creative lighting effects. Nikolai may have comments about this.

WolfOnDigital

ziggy53 wrote:

Jeff,

You "need" to shoot RAW. No question about it, really.

Use an 18 percent gray card at the model's location and meter off of that for best exposure. Use a calibrated white target for white balance and do a test anytime the light changes or you change locations.

Develop a RAW workflow that includes using the white target in the image to set your starting point for white balance.

Work on lighting the subject and choosing an appropriate exposure for the situation which includes both subject movement and camera shake. Once you gain control over lighting, use manual exposure for best results, especially if you used the gray card to establish your exposure.

Alternately, you can use an exposure meter to gauge proper exposure but be sure to calibrate the meter to your camera before trusting the results. Either reflective or incident meter will work with the appropriate technique.

Thanks ziggy.
Yep I believe I need to start shooting RAW.
I just at the moment only have 2 memory cards and each 1 GB
I need to buy a 2 or 3 4GB or higher as last shoot I shot almost 200 images
OR bring my laptop with me download the mem card to the laptop during the shoot if I run out of space. lol
I have a calibrated White balance target from photo vision I bought and should do what you suggest at start of each shoot and shoot the target as the light changes as you suggest.
When you say use "Manual Exposure" what do you mean shoot in full manual mode or choose the metering mode.
I have evaluative, center, and 9%

WolfOnDigital

Thanks
All great points.
Well listened to and will be applied as I shoot.


I definitley am more comfortable since I went to AV mode then fully auto mode.
I agree with you about the LCD screen NOT being an indicator of focus etc.
I thought i was off on my focus on some shots recent shoot but when I looked at the uploaded images more were in focus after some unsharp tweaking then I would have imagined.
Need to break out this calibration I spent money on a while back. lol
And yes I would love to when the budget allows me to but a sekonic meter!
Always loved using my friends in the past.

ziggy53

WolfOnDigital wrote:

... When you say use "Manual Exposure" what do you mean shoot in full manual mode or choose the metering mode.
I have evaluative, center, and 9%

If you have control over the lighting then use full manual exposure control and the partial/9 percent metering mode. Position the gray card at the subject position and take a reading trying to fill the center circle in the viewfinder with the gray card. (It doesn't need to be in focus.) Adjust the exposure until the in-camera exposure meter centers.

Now remove the card and take a test exposure. Check the image with the histogram and blinkies. If the histogram looks OK and there are no blinkies, at least no blinkies in the important areas of the image, you are probably at or close to optimal exposure if your tonal values are within the tonal range of the imager.

If your tones are "well" within acceptable values make sure you "expose to the right" to make best use of the imager and reduce image noise.

If the histogram and/or blinkies indicates that your tonal ranges are beyond the dynamic range of the imager, then you may need to adjust lighting and get shadow and highlight values within range. Crushed blacks and bleached whites need to be dealt with through lighting control.