Focus problem? at DVinfo.net

Hedley Wright · September 2nd, 2008, 04:45 AM

My Z1 suddenly seems to be giving a very soft picture. I would expect my Z7 to be sharper with the better lens but this much? Z1 v Z7 sharpness - a set on Flickr

Any ideas please?

Greg Laves · September 2nd, 2008, 05:04 PM

First of all, you have the gain set to 3 db on the Z1 and it is set to 0 db on the Z7. That will make some difference. Plus, I think it states that the Z1 focus is set to 15 meters. To my eye I would guess that the subjects are more like 8 meters away. But it is hard to judge that from your still.

Hedley Wright · September 3rd, 2008, 01:40 AM

Quote:

Originally Posted by Greg Laves

First of all, you have the gain set to 3 db on the Z1 and it is set to 0 db on the Z7. That will make some difference. Plus, I think it states that the Z1 focus is set to 15 meters. To my eye I would guess that the subjects are more like 8 meters away. But it is hard to judge that from your still.

Thanks for your thoughts Greg. I'll do a test in good lighting at 0dB both cameras, though I wouldn't expect 3dB to make a great deal of difference. The softness is more apparent in video as opposed to stills.

My point was that nothing appears to be in focus - the camera was locked off for the service and focus set to allow for that but there is nothing sharp at ANY distance. Did you check out the original size option on Flickr?

Greg Laves · September 3rd, 2008, 08:48 AM

You are right Hedley. Upon further inspection after a good nights sleep, the Z1 image is not good. Actually it looks a lot like motion blurring. Like someone taking a picture with a DSLR and jerking the shutter release. Was image stabilization turned on?

Dylan Pank · September 3rd, 2008, 09:02 AM

I notice no interlacing artefacts in the frames. How were the shots de-interlaced: in camera or in post? If you set the Z1 to cineframe (its fake progressive mode) it looses 50% of vertical res' as it just dumps a field.

If you were shooting progressive on the Z7 I'd assume it was in a true progressive mode which gives a you a resolution of about 1440*810 from the CCDs so would appear much sharper. Looking at the 1024*576 version of the Z1 image on flickr, it looks about right for standard def if just a little soft. Using cineframe would knock you back to about standard def resolution (albeit good quality progressive scan standard def).

What setting do you have the sharpness on on the Z1? The Z1 relies a lot on electronic in camera sharpening to get a sharp image. I'd suggest shooting some static shots (i.e lock down tripod) with a lot of detail (cityscapes are good for this) with the Z1 with cineframe off and sharpening at about 7-9, zoomed in to about the middle of the lens at F2.8-4 (this is where the lens performs best, use shutter speed/ND filter to get the exposure right), gain at 0dB. Make sure Autofocus is off and focus to infinity. That should show up any issues with the lens (such as backfocus)

Hedley Wright · September 3rd, 2008, 10:13 AM

Quote:

Originally Posted by Greg Laves

You are right Hedley. Upon further inspection after a good nights sleep, the Z1 image is not good. Actually it looks a lot like motion blurring. Like someone taking a picture with a DSLR and jerking the shutter release. Was image stabilization turned on?

Interesting point Greg - I was assuming it might be a back focus problem and hadn't considered the OIS. It would have to be a problem with the OIS though as I have always had it on for locked off shots and have only recently noticed the image softness.

Hedley Wright · September 3rd, 2008, 10:23 AM

Quote:

Originally Posted by Dylan Pank

How were the shots de-interlaced: in camera or in post?

The format is HVD50i for both cameras, stills taken post from the Edius still frame exporter to jpg, upper field only.

Quote:

Originally Posted by Dylan Pank

What setting do you have the sharpness on on the Z1? The Z1 relies a lot on electronic in camera sharpening to get a sharp image.

Z1 was set to 12 (in an attempt to improve matters), the Z7 at 5.

Quote:

Originally Posted by Dylan Pank

I'd suggest shooting some static shots (i.e lock down tripod) with a lot of detail (cityscapes are good for this) with the Z1 with cineframe off and sharpening at about 7-9, zoomed in to about the middle of the lens at F2.8-4 (this is where the lens performs best, use shutter speed/ND filter to get the exposure right), gain at 0dB. Make sure Autofocus is off and focus to infinity. That should show up any issues with the lens (such as backfocus)

Next job - thanks.

Dylan Pank · September 3rd, 2008, 01:26 PM

Hedley, it would be best to upload frame grabs without any de-interlacing as that we it's easier to see what are issues related to the cam itself rather than an effect of the de-interlacing process. it may be annoying to see those jaggies on a still but it's all the better to assess the sharpness where there are not interlacing artefacts.

I'm, surprised to see you had the sharpness up so high on the Z1 as it's really not evident in the final image. I'd really expect to see sharp edge enhancement at that level.

Without looking at the camera first hand I obviously can't be certain, but from your descriptions I'm beginning to suspect it may be a lens problem, especially when you say it "suddenly" got a lot softer.

September 2nd, 2008, 04:45 AM	#1
Hedley Wright Regular Crew Join Date: Aug 2004 Location: England Posts: 45	Focus problem? My Z1 suddenly seems to be giving a very soft picture. I would expect my Z7 to be sharper with the better lens but this much? Z1 v Z7 sharpness - a set on Flickr Any ideas please?

September 2nd, 2008, 05:04 PM	#2
Greg Laves Major Player Join Date: Nov 2007 Location: Corpus Christi, TX Posts: 640	First of all, you have the gain set to 3 db on the Z1 and it is set to 0 db on the Z7. That will make some difference. Plus, I think it states that the Z1 focus is set to 15 meters. To my eye I would guess that the subjects are more like 8 meters away. But it is hard to judge that from your still.

September 3rd, 2008, 08:48 AM	#4
Greg Laves Major Player Join Date: Nov 2007 Location: Corpus Christi, TX Posts: 640	You are right Hedley. Upon further inspection after a good nights sleep, the Z1 image is not good. Actually it looks a lot like motion blurring. Like someone taking a picture with a DSLR and jerking the shutter release. Was image stabilization turned on?

September 3rd, 2008, 09:02 AM	#5
Dylan Pank Major Player Join Date: Nov 2004 Location: Portsmouth, UK Posts: 611	I notice no interlacing artefacts in the frames. How were the shots de-interlaced: in camera or in post? If you set the Z1 to cineframe (its fake progressive mode) it looses 50% of vertical res' as it just dumps a field. If you were shooting progressive on the Z7 I'd assume it was in a true progressive mode which gives a you a resolution of about 1440810 from the CCDs so would appear much sharper. Looking at the 1024576 version of the Z1 image on flickr, it looks about right for standard def if just a little soft. Using cineframe would knock you back to about standard def resolution (albeit good quality progressive scan standard def). What setting do you have the sharpness on on the Z1? The Z1 relies a lot on electronic in camera sharpening to get a sharp image. I'd suggest shooting some static shots (i.e lock down tripod) with a lot of detail (cityscapes are good for this) with the Z1 with cineframe off and sharpening at about 7-9, zoomed in to about the middle of the lens at F2.8-4 (this is where the lens performs best, use shutter speed/ND filter to get the exposure right), gain at 0dB. Make sure Autofocus is off and focus to infinity. That should show up any issues with the lens (such as backfocus)

September 3rd, 2008, 01:26 PM	#8
Dylan Pank Major Player Join Date: Nov 2004 Location: Portsmouth, UK Posts: 611	Hedley, it would be best to upload frame grabs without any de-interlacing as that we it's easier to see what are issues related to the cam itself rather than an effect of the de-interlacing process. it may be annoying to see those jaggies on a still but it's all the better to assess the sharpness where there are not interlacing artefacts. I'm, surprised to see you had the sharpness up so high on the Z1 as it's really not evident in the final image. I'd really expect to see sharp edge enhancement at that level. Without looking at the camera first hand I obviously can't be certain, but from your descriptions I'm beginning to suspect it may be a lens problem, especially when you say it "suddenly" got a lot softer.