Calibrating DA 55-300mm ED WR

SharkyCA · 09-27-2018, 08:26 AM

I have not been overly happy with this lens DA 55-300mm ED WR since I got it as I felt the focus was too soft at the long end.
I tried making a tool for focus adjustment found on the internet, the results of my attempt is here, the first photo is before doing a fine tuning AF adjustment and the second photo is after a plus 5 step.

I am posting these here for any feed back which may help me and others. I have also included a link to these photos on Flickr as they may be more visible.
Focus Adjustment | Flickr

Attached Images

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JohnX · 09-27-2018, 11:32 AM

The critical focus point of zooms invariably changes through its range, so when performing AF adjustment you might want to (a) concentrate on the focal length you use most/want to use, so in this case 300, or (b), check at long, middle and short focal lengths, then average the adjustment.

Penview52 · 09-27-2018, 12:37 PM

>> the second photo is after a plus 5 step<<

The DA 55-300 default setting is for far distant object and not for closer object. You adjusted +5 to make the object closer and gives a sharp object. This would mean that for every distance where you stand in - you will have to adjust the AF to get the correct sharpness which is not advisable. You will have to use other lens intended for closer object, and this lens is for far distant object. At any focal length you can still get sharpness but you will have to adjust the auto focus that fits your needs. Apply AF adjustment for this lens only.

John says" so when performing AF adjustment you might want to (a) concentrate on the focal length you use most " which is true that you must determine how far you are from the target object and adjust the AF.

SharkyCA · 09-27-2018, 02:24 PM - **1 Like**

Originally posted by Penview52

>> the second photo is after a plus 5 step<<

The DA 55-300 default setting is for far distant object and not for closer object. You adjusted +5 to make the object closer and gives a sharp object. This would mean that for every distance where you stand in - you will have to adjust the AF to get the correct sharpness which is not advisable. You will have to use other lens intended for closer object, and this lens is for far distant object. At any focal length you can still get sharpness but you will have to adjust the auto focus that fits your needs. Apply AF adjustment for this lens only.

John says" so when performing AF adjustment you might want to (a) concentrate on the focal length you use most " which is true that you must determine how far you are from the target object and adjust the AF.

I think I get your meaning but it was at 300 I was getting soft focus, I am using a K70 which will remember up to 20 lenses. I will try it and see how it goes, not difficult to go back to factory default, thanks for the input.

bschriver11 · 09-27-2018, 02:58 PM

I think he is referring to focus breathing but i could be wrong? Your only at 300mm at or near infinity focus, when you focus on something close you lose magnification as the lenses move to focus on a near object.

**rogerstg** · 09-27-2018, 03:00 PM

It's hard to tell anything since there's ~2/3 stop difference in exposure (1/30th v 1/50th). The higher contrast of the darker photo will tend to make the black/white areas seem sharper. Plus there's the effect of the camera's own processing of the two differently exposed shots.

Try using the same exposure with the lowest ISO, and if possible, move the camera closer for shallower DoF

Penview52 · 09-27-2018, 03:35 PM

..."it was at 300 I was getting soft focus."

At 300 mm the object is close and the target object is not within ( inside ) the acceptable dept of field ( resulting soft focus ). That is why applying +5 correct the position of the target object within the dept of field.

As Roger said " move the camera closer for shallower DoF" one way to get the right focus or do select a wider aperture opening.

I posted apply AF adjustment to this lens only because it will affect other lens you will use.

Last edited by Penview52; 09-27-2018 at 03:47 PM.

pschlute · 09-27-2018, 08:04 PM

Even looking at the Flickr pictures I am struggling to identify backfocus in the "default" picture

SharkyCA · 09-28-2018, 06:05 AM

Originally posted by rogerstg

It's hard to tell anything since there's ~2/3 stop difference in exposure (1/30th v 1/50th). The higher contrast of the darker photo will tend to make the black/white areas seem sharper. Plus there's the effect of the camera's own processing of the two differently exposed shots.

Try using the same exposure with the lowest ISO, and if possible, move the camera closer for shallower DoF

Originally posted by Penview52

..."it was at 300 I was getting soft focus."

At 300 mm the object is close and the target object is not within ( inside ) the acceptable dept of field ( resulting soft focus ). That is why applying +5 correct the position of the target object within the dept of field.

As Roger said " move the camera closer for shallower DoF" one way to get the right focus or do select a wider aperture opening.

I posted apply AF adjustment to this lens only because it will affect other lens you will use.

Originally posted by pschlute

Even looking at the Flickr pictures I am struggling to identify backfocus in the "default" picture

I agree with a lot of what has been said here, I had the camera set at the same distance from the "target" in both photos, set on "TAV" for constant F stop of 5.8 not sure why one was so much darker than the other unless it was the speed that changed for some reason. Also the target printed on an "ink jet" throws more into the mix. My original problem was taking shots of extremely long distance, not noticeable if only 30 or 40 feet away but very soft if taking shots into the sky, these shots of clouds were taken after the 5 point adjustment I will try this for a few days and see how they turn out.

Thanks for all your input, what a great resource pentaxforums.com is!

This photo is not processed other than upload size!

Same photo PP with Photodirector8!

Penview52 · 09-28-2018, 12:09 PM - **1 Like**

The darker photo is caused by shake of the camera, except there is post processing done.

There is dust in the photo. Dust affects the sensor function. Determine where is it coming from.

SharkyCA · 09-29-2018, 02:45 AM

Originally posted by Penview52

The darker photo is caused by shake of the camera, except there is post processing done.

There is dust in the photo. Dust affects the sensor function. Determine where is it coming from.

They are both the same photos, 1 processed and 1 not, could be camera shake BUT not dust. Only posted to display shot AFTER AF adjustment.

SharkyCA · 09-29-2018, 03:19 AM

Originally posted by Penview52

..."it was at 300 I was getting soft focus."

At 300 mm the object is close and the target object is not within ( inside ) the acceptable dept of field ( resulting soft focus ). That is why applying +5 correct the position of the target object within the dept of field.

As Roger said " move the camera closer for shallower DoF" one way to get the right focus or do select a wider aperture opening.

I posted apply AF adjustment to this lens only because it will affect other lens you will use.

The camera was about 20' away dof should be 19.8 to 20.1' AF adjustment applied ONLY to one lens. SEE ATTACHED.

pschlute · 09-29-2018, 03:32 AM - **1 Like**

Originally posted by SharkyCA

could be camera shake BUT not dust

i think he ws saying you have dust on the sensor which is visible in both pictures. But this is a side issue, nothing to do with the AF

I suggest you stick to the focus chart to determine if you have a focus problem. reset the camera to 0 adjustment and redo the test. You will need to take about 10 shots, each time moving the focus ring between shots, you want to make the camera work to acquire focus. A single test is not enough, camera AF is not that consistent. let us know what you see in those 10 pictures.

Then do a test by focussing on a distant object such a brick wall. Do 10 tests again. This wont show up any FF/BF but it will show if your camera/lens is capable of achieving focus at all.

Penview52 · 09-29-2018, 05:51 AM

"... The camera was about 20' away dof should be 19.8 to 20.1' AF adjustment applied .."

Ok you say the focus is within the DoF, applied to this lens only, but the result is dark photo.

The auto focusing is dull. Are you using filters?,
I suggest that contrast AF is set to spot, and AF active area is also spot. Do not use filter but use lens hood and tripod.
Lastly use other lens that works good focusing then change to this 55-300 without any change of settings.

pschlute · 09-29-2018, 03:02 PM

Originally posted by Penview52

I suggest that contrast AF is set to spot

Contrast detect AF is a Live View mode. Nothing to do with the OP's problems which relate to viewfinder AF.

09-29-2018, 03:32 AM - 1 Like	#13
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,192	Originally posted by SharkyCA could be camera shake BUT not dust i think he ws saying you have dust on the sensor which is visible in both pictures. But this is a side issue, nothing to do with the AF I suggest you stick to the focus chart to determine if you have a focus problem. reset the camera to 0 adjustment and redo the test. You will need to take about 10 shots, each time moving the focus ring between shots, you want to make the camera work to acquire focus. A single test is not enough, camera AF is not that consistent. let us know what you see in those 10 pictures. Then do a test by focussing on a distant object such a brick wall. Do 10 tests again. This wont show up any FF/BF but it will show if your camera/lens is capable of achieving focus at all. Last edited by pschlute; 09-29-2018 at 03:42 AM.

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09-27-2018, 11:32 AM	#2
JohnX Pentaxian Join Date: Jul 2009 Location: London Posts: 1,116	The critical focus point of zooms invariably changes through its range, so when performing AF adjustment you might want to (a) concentrate on the focal length you use most/want to use, so in this case 300, or (b), check at long, middle and short focal lengths, then average the adjustment.

09-27-2018, 12:37 PM	#3
Penview52 Veteran Member Join Date: Apr 2017 Photos: Albums Posts: 327	>> the second photo is after a plus 5 step<< The DA 55-300 default setting is for far distant object and not for closer object. You adjusted +5 to make the object closer and gives a sharp object. This would mean that for every distance where you stand in - you will have to adjust the AF to get the correct sharpness which is not advisable. You will have to use other lens intended for closer object, and this lens is for far distant object. At any focal length you can still get sharpness but you will have to adjust the auto focus that fits your needs. Apply AF adjustment for this lens only. John says" so when performing AF adjustment you might want to (a) concentrate on the focal length you use most " which is true that you must determine how far you are from the target object and adjust the AF.

09-27-2018, 02:24 PM - 1 Like	#4
SharkyCA Pentaxian Join Date: Sep 2017 Location: Carleton Place, Ontario, Canada Photos: Gallery Posts: 806 Original Poster	Originally posted by Penview52 >> the second photo is after a plus 5 step<< The DA 55-300 default setting is for far distant object and not for closer object. You adjusted +5 to make the object closer and gives a sharp object. This would mean that for every distance where you stand in - you will have to adjust the AF to get the correct sharpness which is not advisable. You will have to use other lens intended for closer object, and this lens is for far distant object. At any focal length you can still get sharpness but you will have to adjust the auto focus that fits your needs. Apply AF adjustment for this lens only. John says" so when performing AF adjustment you might want to (a) concentrate on the focal length you use most " which is true that you must determine how far you are from the target object and adjust the AF. I think I get your meaning but it was at 300 I was getting soft focus, I am using a K70 which will remember up to 20 lenses. I will try it and see how it goes, not difficult to go back to factory default, thanks for the input.

09-27-2018, 02:58 PM	#5
bschriver11 Pentaxian Join Date: May 2008 Location: Maryland Photos: Gallery Posts: 558	I think he is referring to focus breathing but i could be wrong? Your only at 300mm at or near infinity focus, when you focus on something close you lose magnification as the lenses move to focus on a near object.

09-27-2018, 03:00 PM	#6
rogerstg Loyal Site Supporter Join Date: Oct 2007 Location: Rhode Island Photos: Albums Posts: 1,168	It's hard to tell anything since there's ~2/3 stop difference in exposure (1/30th v 1/50th). The higher contrast of the darker photo will tend to make the black/white areas seem sharper. Plus there's the effect of the camera's own processing of the two differently exposed shots. Try using the same exposure with the lowest ISO, and if possible, move the camera closer for shallower DoF

09-27-2018, 03:35 PM	#7
Penview52 Veteran Member Join Date: Apr 2017 Photos: Albums Posts: 327	..."it was at 300 I was getting soft focus." At 300 mm the object is close and the target object is not within ( inside ) the acceptable dept of field ( resulting soft focus ). That is why applying +5 correct the position of the target object within the dept of field. As Roger said " move the camera closer for shallower DoF" one way to get the right focus or do select a wider aperture opening. I posted apply AF adjustment to this lens only because it will affect other lens you will use. Last edited by Penview52; 09-27-2018 at 03:47 PM.

09-27-2018, 08:04 PM	#8
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,192	Even looking at the Flickr pictures I am struggling to identify backfocus in the "default" picture

09-28-2018, 06:05 AM	#9
SharkyCA Pentaxian Join Date: Sep 2017 Location: Carleton Place, Ontario, Canada Photos: Gallery Posts: 806 Original Poster	Originally posted by rogerstg It's hard to tell anything since there's ~2/3 stop difference in exposure (1/30th v 1/50th). The higher contrast of the darker photo will tend to make the black/white areas seem sharper. Plus there's the effect of the camera's own processing of the two differently exposed shots. Try using the same exposure with the lowest ISO, and if possible, move the camera closer for shallower DoF Originally posted by Penview52 ..."it was at 300 I was getting soft focus." At 300 mm the object is close and the target object is not within ( inside ) the acceptable dept of field ( resulting soft focus ). That is why applying +5 correct the position of the target object within the dept of field. As Roger said " move the camera closer for shallower DoF" one way to get the right focus or do select a wider aperture opening. I posted apply AF adjustment to this lens only because it will affect other lens you will use. Originally posted by pschlute Even looking at the Flickr pictures I am struggling to identify backfocus in the "default" picture I agree with a lot of what has been said here, I had the camera set at the same distance from the "target" in both photos, set on "TAV" for constant F stop of 5.8 not sure why one was so much darker than the other unless it was the speed that changed for some reason. Also the target printed on an "ink jet" throws more into the mix. My original problem was taking shots of extremely long distance, not noticeable if only 30 or 40 feet away but very soft if taking shots into the sky, these shots of clouds were taken after the 5 point adjustment I will try this for a few days and see how they turn out. Thanks for all your input, what a great resource pentaxforums.com is! This photo is not processed other than upload size! Same photo PP with Photodirector8!

09-28-2018, 12:09 PM - 1 Like	#10
Penview52 Veteran Member Join Date: Apr 2017 Photos: Albums Posts: 327	The darker photo is caused by shake of the camera, except there is post processing done. There is dust in the photo. Dust affects the sensor function. Determine where is it coming from.

09-29-2018, 02:45 AM	#11
SharkyCA Pentaxian Join Date: Sep 2017 Location: Carleton Place, Ontario, Canada Photos: Gallery Posts: 806 Original Poster	Originally posted by Penview52 The darker photo is caused by shake of the camera, except there is post processing done. There is dust in the photo. Dust affects the sensor function. Determine where is it coming from. They are both the same photos, 1 processed and 1 not, could be camera shake BUT not dust. Only posted to display shot AFTER AF adjustment.

09-29-2018, 05:51 AM	#14
Penview52 Veteran Member Join Date: Apr 2017 Photos: Albums Posts: 327	"... The camera was about 20' away dof should be 19.8 to 20.1' AF adjustment applied .." Ok you say the focus is within the DoF, applied to this lens only, but the result is dark photo. The auto focusing is dull. Are you using filters?, I suggest that contrast AF is set to spot, and AF active area is also spot. Do not use filter but use lens hood and tripod. Lastly use other lens that works good focusing then change to this 55-300 without any change of settings.

09-29-2018, 03:02 PM	#15
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,192	Originally posted by Penview52 I suggest that contrast AF is set to spot Contrast detect AF is a Live View mode. Nothing to do with the OP's problems which relate to viewfinder AF.

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