Win a Pentax Limited Lens: Raffle Now Live!

pschlute · 01-14-2017, 06:31 PM

Seeing as the flash will only be triggered after the AF has "locked-on", how will that help ?

**TwoUptons** · 01-14-2017, 07:11 PM

Removes odds of camera shake since the exposure speed is now driven by the flash duration...

stevebrot · 01-14-2017, 08:20 PM - **2 Likes**

Originally posted by TwoUptons

Removes odds of camera shake since the exposure speed is now driven by the flash duration...

Or one could simply use a tripod and time delay. Rather than flash and the chance of ghosting, I would suggest fairly bright light (natural if possible*) to optimize the AF performance coupled with tripod low/moderate ISO and higher shutter speed.

Steve

* Although it is not as big a problem today as in the past, PDAF accuracy may be wavelength sensitive.

pschlute · 01-15-2017, 09:34 AM

Originally posted by TwoUptons

Removes odds of camera shake since the exposure speed is now driven by the flash duration...

A serious AF calibration should not have any camera movement at all...ie use a tripod. You need to be able to take a number of consecutive pictures to arrive at the correct setting, and only by using a tripod can you make sure they are all identical.

stevebrot · 01-15-2017, 11:50 AM

Originally posted by pschlute

You need to be able to take a number of consecutive pictures to arrive at the correct setting, and only by using a tripod can you make sure they are all identical.

Thank you for making this point. Probably the most common cause of AF fine adjust frustration is using single focus attempts as the basis for adjustment and/or to confirm whether the adjustment worked. In many cases, the "scatter" is greater than the actual adjustment amount and success may be difficult to assess. Multiple focus attempts is a strong point of the Dot Line method and the basis for automated analysis with current model LensAlign product.

Steve

pschlute · 01-15-2017, 05:19 PM - **1 Like**

Yes Steve. In fact I think many folks will be quite shocked the first time the do a AF test. You get yourself all set up and then decide to make a note of where on the lens distance scale the AF is stopping the focus ring each time you do say 10 test runs. They should all be identical right ? Think again !!

**niceshot** · 01-15-2017, 05:21 PM - **1 Like**

Originally posted by stevebrot

Or one could simply use a tripod and time delay. Rather than flash and the chance of ghosting, I would suggest fairly bright light (natural if possible*) to optimize the AF performance coupled with tripod low/moderate ISO and higher shutter speed.

Steve

* Although it is not as big a problem today as in the past, PDAF accuracy may be wavelength sensitive.

Steve you are absolutely 100 percent right.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
My AF fine tune experience	DeadJohn	Pentax K-1 & K-1 II	27	02-06-2017 12:29 PM
PZ-70 Autofocus not working.	Mister Mike	Film SLRs and Compact Film Cameras	3	07-16-2016 04:46 AM
How do you fine-tune Autofocus?	fullmental	Troubleshooting and Beginner Help	5	02-21-2016 07:14 AM
SFXn autofocus not working	Jonathan Mac	Film SLRs and Compact Film Cameras	4	08-03-2015 01:24 AM
Calibrating lens beyond fine tune?	phidias81	Troubleshooting and Beginner Help	2	04-25-2015 08:08 PM

01-14-2017, 06:31 PM	#16
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,222	Seeing as the flash will only be triggered after the AF has "locked-on", how will that help ?

01-14-2017, 07:11 PM	#17
TwoUptons Loyal Site Supporter Join Date: Nov 2015 Photos: Albums Posts: 4,227	Removes odds of camera shake since the exposure speed is now driven by the flash duration...

01-14-2017, 08:20 PM - 2 Likes	#18
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by TwoUptons Removes odds of camera shake since the exposure speed is now driven by the flash duration... Or one could simply use a tripod and time delay. Rather than flash and the chance of ghosting, I would suggest fairly bright light (natural if possible) to optimize the AF performance coupled with tripod low/moderate ISO and higher shutter speed. Steve Although it is not as big a problem today as in the past, PDAF accuracy may be wavelength sensitive.

01-15-2017, 09:34 AM	#19
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,222	Originally posted by TwoUptons Removes odds of camera shake since the exposure speed is now driven by the flash duration... A serious AF calibration should not have any camera movement at all...ie use a tripod. You need to be able to take a number of consecutive pictures to arrive at the correct setting, and only by using a tripod can you make sure they are all identical.

01-15-2017, 11:50 AM	#20
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by pschlute You need to be able to take a number of consecutive pictures to arrive at the correct setting, and only by using a tripod can you make sure they are all identical. Thank you for making this point. Probably the most common cause of AF fine adjust frustration is using single focus attempts as the basis for adjustment and/or to confirm whether the adjustment worked. In many cases, the "scatter" is greater than the actual adjustment amount and success may be difficult to assess. Multiple focus attempts is a strong point of the Dot Line method and the basis for automated analysis with current model LensAlign product. Steve

01-15-2017, 05:19 PM - 1 Like	#21
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,222	Yes Steve. In fact I think many folks will be quite shocked the first time the do a AF test. You get yourself all set up and then decide to make a note of where on the lens distance scale the AF is stopping the focus ring each time you do say 10 test runs. They should all be identical right ? Think again !!

01-15-2017, 05:21 PM - 1 Like	#22
niceshot Site Supporter Join Date: Mar 2014 Location: NY Photos: Gallery Posts: 1,565	Originally posted by stevebrot Or one could simply use a tripod and time delay. Rather than flash and the chance of ghosting, I would suggest fairly bright light (natural if possible) to optimize the AF performance coupled with tripod low/moderate ISO and higher shutter speed. Steve Although it is not as big a problem today as in the past, PDAF accuracy may be wavelength sensitive. Steve you are absolutely 100 percent right.

Autofocus fine tune not working

Win a Pentax Limited Lens: Raffle Now Live!