Confused with lens focus procedure

[Jerry_K]

Tonight I gave wide field AP good try (my very first) with 450D and 75-300mm zoom set at 300mm. In order to focus using BYE I had to turn on AF on the lens. However, when I took a Preview shot it got aborted because AF was on and I got error message that BYE was trying to focus but couldn't because the AF was on. Why and how would BYE focus my lens after I have painstakingly focused the lens already? On top of it, I don't want to touch the lens/camera to turn off AF for obvious reason. Am I missing something?

BTW, the focus works flawlessly, I got 2.1 FWHM on Kaus Borealis (my plan was M8 & M20).

So question is: why can't I keep AF on for shooting my plan? I was running BYE v3.1 RC4.

Jerry

[strikele]

I do not seem to have this issue at all and I have used the lens focus routine a few times.  I routinely have my camera set to "back button focus"in the custom functions, which removes focusing from the shutter button to, in the case of my 500D, the * button.  The lens I use needs to be in AF.   In BYE, the camera focuses when I push the focus buttons, and does not do so when I take the image (lens still in AF).  You might give this a try for your camera/lens combination to see if it will work for you.

 

Thanks Leslie,

my 450D doesn't seem to have that custom option. What exactly is it called on Custom Functions menu and what number is assigned to this button? It is a muted point, though, as everything works just fine. No idea why it didn't work last night.

Thanks, Jerry

 

Jerry, it should work on your 450 because it worked on the XT that I used to have.  "Back button focus" is the name that this function is usually referred to in photography forums.  On my 500D, it is custom function 10, called by Canon "Shutter/AE lock button".  I have three settings for this function on my camera, and I use setting 1, called " AE lock/AF".

 

Leslie

[Jerry_K]

 

Jerry, it should work on your 450 because it worked on the XT that I used to have.  "Back button focus" is the name that this function is usually referred to in photography forums.  On my 500D, it is custom function 10, called by Canon "Shutter/AE lock button".  I have three settings for this function on my camera, and I use setting 1, called " AE lock/AF".

 

Leslie

 

Thanks, Leslie.

I am so confused now! Last night I was doing wide field M31 and to my astonishment after focusing I was forced to toggle AF switch to off. I was astonished because when I tried it during day it worked perfectly at least dozen times without having to turn the AF off. This morning I tried again and I didn't have to switch. So why last night was different? I just can't wrap my head around it. Anyway, I did go to function 10 and switched to setting 1. I'll se tonight what will happen.

Thanks again for the tip,

Jerry

[s3igell]

I am so confused now! Last night I was doing wide field M31 and to my astonishment after focusing I was forced to toggle AF switch to off. I was astonished because when I tried it during day it worked perfectly at least dozen times without having to turn the AF off. This morning I tried again and I didn't have to switch. So why last night was different? I just can't wrap my head around it. Anyway, I did go to function 10 and switched to setting 1. I'll se tonight what will happen.

Thanks again for the tip,

Jerry

 

One difference between Daytime and Nighttime Focusing:  In Daytime, the Camera is left with a focused Image that is bright enough for the AF to continue working - even on subsequent shots.  At Night, after working through a "Manual Focus using BYE", the next "Shutter Press" will attempt an AF Session against a FOV that is far too Dark to allow continued Focus on the Target DSO/Star (unless possibly a Bright Star centered directly on the Central Cross-Focus Sensor).  In other words, in Daytime it is performing an unwanted AF and is quickly Successful, while at Night it is also performing an unwanted AF but Failing leading the User to finally notice that an AF has occurred.  (Make sense ??)

A better Daytime test would be to start the same Focus procedure, but place a piece of paper in front of the Optics before trying the Image Session.  If the Camera starts to Seek Focus, then your AF Switch will need to be flipped to OFF after the Focusing session.

[Jerry_K]

 

One difference between Daytime and Nighttime Focusing:  In Daytime, the Camera is left with a focused Image that is bright enough for the AF to continue working - even on subsequent shots.  At Night, after working through a "Manual Focus using BYE", the next "Shutter Press" will attempt an AF Session against a FOV that is far too Dark to allow continued Focus on the Target DSO/Star (unless possibly a Bright Star centered directly on the Central Cross-Focus Sensor).  In other words, in Daytime it is performing an unwanted AF and is quickly Successful, while at Night it is also performing an unwanted AF but Failing leading the User to finally notice that an AF has occurred.  (Make sense ??)

A better Daytime test would be to start the same Focus procedure, but place a piece of paper in front of the Optics before trying the Image Session.  If the Camera starts to Seek Focus, then your AF Switch will need to be flipped to OFF after the Focusing session.

 

Hey, message from you via email notification is different from forum message! Last paragraph wasn't there. Oh, I can see it was edited. I was going to say that I will put lens cap on and try it. Excellent observation!

Thanks, I'll keep you posted.

Jerry 

[Jerry_K]

One difference between Daytime and Nighttime Focusing:  In Daytime, the Camera is left with a focused Image that is bright enough for the AF to continue working - even on subsequent shots.  At Night, after working through a "Manual Focus using BYE", the next "Shutter Press" will attempt an AF Session against a FOV that is far too Dark to allow continued Focus on the Target DSO/Star (unless possibly a Bright Star centered directly on the Central Cross-Focus Sensor).  In other words, in Daytime it is performing an unwanted AF and is quickly Successful, while at Night it is also performing an unwanted AF but Failing leading the User to finally notice that an AF has occurred.  (Make sense ??)

A better Daytime test would be to start the same Focus procedure, but place a piece of paper in front of the Optics before trying the Image Session.  If the Camera starts to Seek Focus, then your AF Switch will need to be flipped to OFF after the Focusing session.

 

 I just put a dark film in front of lens, focused on LED bulb 20 feet away, switched to Imaging, put the lens cap on and fired. And BYE went through its paces without a hitch. I had Special Function #10 set to 1. However, and here is a kicker thanks to Leslie, when I switched to default 0 the camera through BYE gave me ERROR. Shane, your theory is absolutely correct.

So boys and girls, if you do not want to touch your lens after focusing, go to Function 10 and select #1, AE lock/AF. And look ma, no hands!

Thanks again Leslie!

Jerry

[astroman133]

For the benefit of others who may change this custom setting...If you change the "Shutter/AE lock button" Custom Setting to AE lock/AF, you will need to use the * button (on my T5i camera it is also the LiveView Zoom Out button) to trigger autofocus for daytime photography, since pressing the shutter halfway down only triggers the automatic exposure function and not auto focus.

[Jerry_K]

For the benefit of others who may change this custom setting...If you change the "Shutter/AE lock button" Custom Setting to AE lock/AF, you will need to use the * button (on my T5i camera it is also the LiveView Zoom Out button) to trigger autofocus for daytime photography, since pressing the shutter halfway down only triggers the automatic exposure function and not auto focus.

Thanks Rick for pointing this out. Since my 450D is full spectrum with only clear glass for infinity focus installed I never use it for daytime, astro only. You are correct, for terrestrial use you have to change the function again or use "*" button on back of camera to autofocus.

Jerry

[DENMONKEY]

here is a quick video which shows the back button focus set up and how to turn off continuous focus on the t4 and 5i which you may find helpful.

Not sure how this may or may not apply to the 450.

 

 

As a new user who hasn't yet done anything more than play with BYE for 5 minutes, I can't give you instructions but with the info provided above I think you will be well on your way.

[Jerry_K]

here is a quick video which shows the back button focus set up and how to turn off continuous focus on the t4 and 5i which you may find helpful.

Not sure how this may or may not apply to the 450.

As a new user who hasn't yet done anything more than play with BYE for 5 minutes, I can't give you instructions but with the info provided above I think you will be well on your way.

 

If you read previous replies you will notice that it was done over a week ago by simply changing one special function. Works like a charm.

Thanks for trying to help,

Jerry

[astroman133]

Jerry,

 

It is not BYE that is trying to adjust focus before the shot, it is the camera.

 

I think that you need to turn the AutoFocus switch off immediately after focusing, but before imaging. I know that it is not ideal, but it is what I have always done when shooting widefield shots.

[Jerry_K]

Jerry,

 

It is not BYE that is trying to adjust focus before the shot, it is the camera.

 

I think that you need to turn the AutoFocus switch off immediately after focusing, but before imaging. I know that it is not ideal, but it is what I have always done when shooting widefield shots.

Rick, to my dismay, I have found this out on my 1st preview shot. It is a bummer as I was getting ready for cold weather remote shooting.Jerry

[s3igell]

Jerry, perhaps you could walk us through the steps you were using for your Focusing and Imaging effort...

[admin]

Guys, controlling the lens IS 100% a lens activity.

 

BYE simply provides buttons that sends the command to the lens.

 

Some lens require that you PUT the lens in AutoFocus mode for it to be controlled via software.  This is a lens limitation and there is nothing software can do.

 

Some lens will allow to be controlled when NOT in AutoFocus mode.  This is great and how it should be for all lens, but sadly it is not the case <_>

 

BYE does not, ever, try to AutoFocus the lens.  This is a 100% function of the lens and WILL always take place if the lens is set to AF when taking a picture.  Sad but true <_>

 

So, the workflow is

 

1) Set your lens to AF (some lens will allow focusing in MF, but most do not)

2) Focus in BYE using the focus buttons (only works if you lens supports it)

3) When you are focused, set the lens to MF

4) Happy imaging.

 

Hope this helps,

 

Guylain

 

 

[strikele]

Guys, controlling the lens IS 100% a lens activity.

 

BYE simply provides buttons that sends the command to the lens.

 

Some lens require that you PUT the lens in AutoFocus mode for it to be controlled via software.  This is a lens limitation and there is nothing software can do.

 

Some lens will allow to be controlled when NOT in AutoFocus mode.  This is great and how it should be for all lens, but sadly it is not the case <_<

 

BYE does not, ever, try to AutoFocus the lens.  This is a 100% function of the lens and WILL always take place if the lens is set to AF when taking a picture.  Sad but true <_<

 

So, the workflow is

 

1) Set your lens to AF (some lens will allow focusing in MF, but most do not)

2) Focus in BYE using the focus buttons (only works if you lens supports it)

3) When you are focused, set the lens to MF

4) Happy imaging.

 

Hope this helps,

 

Guylain

 

[Jerry_K]

Jerry, perhaps you could walk us through the steps you were using for your Focusing and Imaging effort...

Shane, see Guylain's reply. This is exactly what I did and had to do. I just hate touching camera after it is focused.

Thanks for trying to help,

Jerry

[Jerry_K]

Guys, controlling the lens IS 100% a lens activity.

 

BYE simply provides buttons that sends the command to the lens.

 

Some lens require that you PUT the lens in AutoFocus mode for it to be controlled via software.  This is a lens limitation and there is nothing software can do.

 

Some lens will allow to be controlled when NOT in AutoFocus mode.  This is great and how it should be for all lens, but sadly it is not the case <_<

 

BYE does not, ever, try to AutoFocus the lens.  This is a 100% function of the lens and WILL always take place if the lens is set to AF when taking a picture.  Sad but true <_<

 

So, the workflow is

 

1) Set your lens to AF (some lens will allow focusing in MF, but most do not)

2) Focus in BYE using the focus buttons (only works if you lens supports it)

3) When you are focused, set the lens to MF

4) Happy imaging.

 

Hope this helps,

 

Guylain

 

Thanks Guylain to clarify the issue. I will check all my Canon lenses and see if all had to be switched off AF. However, I am happy to say that after switching AF off the stars stayed pin sharp at 2.6 - 2.8 FWHM.

Jerry

[strikele]

I do not seem to have this issue at all and I have used the lens focus routine a few times.  I routinely have my camera set to "back button focus"in the custom functions, which removes focusing from the shutter button to, in the case of my 500D, the * button.  The lens I use needs to be in AF.   In BYE, the camera focuses when I push the focus buttons, and does not do so when I take the image (lens still in AF).  You might give this a try for your camera/lens combination to see if it will work for you.

[admin]

I do not seem to have this issue at all and I have used the lens focus routine a few times.  I routinely have my camera set to "back button focus"in the custom functions, which removes focusing from the shutter button to, in the case of my 500D, the * button.  The lens I use needs to be in AF.   In BYE, the camera focuses when I push the focus buttons, and does not do so when I take the image (lens still in AF).  You might give this a try for your camera/lens combination to see if it will work for you.

 

This is interesting, I'll have to try it.

 

 

[Jerry_K]

I do not seem to have this issue at all and I have used the lens focus routine a few times.  I routinely have my camera set to "back button focus"in the custom functions, which removes focusing from the shutter button to, in the case of my 500D, the * button.  The lens I use needs to be in AF.   In BYE, the camera focuses when I push the focus buttons, and does not do so when I take the image (lens still in AF).  You might give this a try for your camera/lens combination to see if it will work for you.

Leslie, I'll be damned but it works now, no issues at all. However, last night I got error messages. Here is excerpt from log file:

 

   at BinaryRivers.Common.Model.CameraModelBase.<>c__DisplayClass1.<CameraTakePictureOnMessageRecieved>b__0()

2014-09-18 20:33:55,821 [CameraTakePictureOnMessageRecieved] INFO  - Imaging session cancelled

2014-09-18 20:33:55,837 [CameraTakePictureOnMessageRecieved] INFO  - Camera is unable to focus; auto-focus may be on

2014-09-18 20:33:55,837 [CameraTakePictureOnMessageRecieved] ERROR - Camera is unable to focus; auto-focus may be on

 

I didn't change anything, same camera, power source and lens. Only thing that is different is that I restarted BYE.

Jerry 

[Jerry_K]

I do not seem to have this issue at all and I have used the lens focus routine a few times.  I routinely have my camera set to "back button focus"in the custom functions, which removes focusing from the shutter button to, in the case of my 500D, the * button.  The lens I use needs to be in AF.   In BYE, the camera focuses when I push the focus buttons, and does not do so when I take the image (lens still in AF).  You might give this a try for your camera/lens combination to see if it will work for you.

 

Thanks Leslie,

my 450D doesn't seem to have that custom option. What exactly is it called on Custom Functions menu and what number is assigned to this button? It is a muted point, though, as everything works just fine. No idea why it didn't work last night.

Thanks, Jerry