FS5: Issue with focus magnification in 4K

N

Newsguy

Well-known member
I have found the peaking on the FS5 LCD to be inaccurate and coming from Sony broadcast viewfinders, it's in a totally different league. Because of this, I tend to use focus mag often during sit down interviews where the subject doesn't sit still. So far, I've shot all of my material in 1080, but today I discovered something (thankfully not during a shoot).

I was running some tests in 4K with a Canon 50mm 1.4. I shot a card with small text, used focus mag, and adjusted. I then shot the same thing in 4k, but when viewing the text in focus mag, it was completely blurry and almost distorted. So I recorded it and ran some tests by zooming in Premiere, and the text is fully in focus, no blur or distortion.

Is this a known issue with the FS5? I've tried searching for this issue but haven't found anything. Basically focus mag is completely useless in 4K. It could be the lens, but I don't know how because when I switch to 1080, focus mag works flawlessly again. Any info or science behind why this is happening is appreciated! Thanks.
 
I haven't had this issue with the FS5, in fact, use the 4x focus mag all the time in both HD and 4K. Peaking is not particularly accurate and the resolution of the LCD is not great., but I have found the 4K mag to be fine.
 
Hmm... I'm going to have to look into it. Up until I tried it in 4K it was working great, and I as well found it to be the only way to gauge my focus in many cases. Maybe it's the canon 50mm, I'll try it with a different lens and report back.
 
Just tested with the 70-200. It also had the same issue. The easiest way to see it is to focus mag on small text. In HD I can get a very tight focus and see the lines get very sharp. In 4K edges aren't nearly as tight and it's really never truly in focus. The only way for me to tell is that I pass the focus point and roll past it. So the tightest it gets still looks a bit soft. The final recorded image looks fine, but something in the resolution change seems to be degrading the IQ when using focus mag.
 
Newsguy said:
Just tested with the 70-200. It also had the same issue. The easiest way to see it is to focus mag on small text. In HD I can get a very tight focus and see the lines get very sharp. In 4K edges aren't nearly as tight and it's really never truly in focus. The only way for me to tell is that I pass the focus point and roll past it. So the tightest it gets still looks a bit soft. The final recorded image looks fine, but something in the resolution change seems to be degrading the IQ when using focus mag.
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Obviously it is only about how the camera implements magnification at this resolution, has nothing to do with the actual recorded IQ.
 
I have the same issue in 4k. I was not happy about this, but learned to work around it. I have been close to buying a external recorder/monitor to get more accurate. I keep hoping firmware would solve this.
 
broughtonfilm said:
Obviously it is only about how the camera implements magnification at this resolution, has nothing to do with the actual recorded IQ.
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Oh so the feature that you use specifically to tighten up the focus shows up out of focus. It can be argued that it doesn't matter what the recorded image looks like since gauging focus with this feature is a crapshoot.
 
Newsguy said:
Oh so the feature that you use specifically to tighten up the focus shows up out of focus. It can be argued that it doesn't matter what the recorded image looks like since gauging focus with this feature is a crapshoot.
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??? It literally is about how the camera scales the image to display as magnified. Edges may appear jagged and not "sharp" but it is plenty detailed to see what is in focus and what isn't.
 
broughtonfilm said:
??? It literally is about how the camera scales the image to display as magnified. Edges may appear jagged and not "sharp" but it is plenty detailed to see what is in focus and what isn't.
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Not in what I'm seeing. If I'm looking at eyelashes or lips, the 4k focus mag is insufficient. If what you're seeing is "plenty detailed" were not seeing the same image. I don't get aliased edges like you're describing, I get soft and almost smudged lines.
 
Newsguy said:
Not in what I'm seeing. If I'm looking at eyelashes or lips, the 4k focus mag is insufficient. If what you're seeing is "plenty detailed" were not seeing the same image. I don't get aliased edges like you're describing, I get soft and almost smudged lines.
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Didn't you say you could still tell the focus based on that? But I don't know, maybe you have a faulty camera, does not hurt to send it to Sony for evaluation...
 
broughtonfilm said:
Didn't you say you could still tell the focus based on that? But I don't know, maybe you have a faulty camera, does not hurt to send it to Sony for evaluation...
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No, I have to roll past the smudged image to a more smudged image and then roll back. I'm gonna call them to see if this is a thing. I wish the factory LCD was better. Even my buddy's 720p ninja blade allows me to check focus without having to punch in.
 
Newsguy said:
No, I have to roll past the smudged image to a more smudged image and then roll back. I'm gonna call them to see if this is a thing. I wish the factory LCD was better. Even my buddy's 720p ninja blade allows me to check focus without having to punch in.
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What you are seeing is perfectly normal. I was just pulling your leg. Just realize that you'll never watch the footage at that level of magnification. Why are you even magnifying the image on your computer after ingesting? What's the point?
 
broughtonfilm said:
What you are seeing is perfectly normal. I was just pulling your leg. Just realize that you'll never watch the footage at that level of magnification. Why are you even magnifying the image on your computer after ingesting? What's the point?
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I magnified the image in post specifically to see if the image was being recorded this way or if it was the LCD. I would never zoom 400% in post otherwise. What caused my curiosity was that when using focus mag in 1080p the image was always sharp and it was easy to grab focus. In 4K there is a big drop in IQ when using focus mag. I was simply running tests to make sure it was just the LCD doing this and nothing was happening internally.
 
Newsguy said:
I magnified the image in post specifically to see if the image was being recorded this way or if it was the LCD. I would never zoom 400% in post otherwise. What caused my curiosity was that when using focus mag in 1080p the image was always sharp and it was easy to grab focus. In 4K there is a big drop in IQ when using focus mag. I was simply running tests to make sure it was just the LCD doing this and nothing was happening internally.
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My point is that even if you miss the focus slightly when using magnification feature, it will not make a visual difference in normal viewing conditions of the footage. Such small error is insignificant. There's no such thing as perfect focus when filming 3-dimensional objects anyway...
 
broughtonfilm said:
My point is that even if you miss the focus slightly when using magnification feature, it will not make a visual difference in normal viewing conditions of the footage. Such small error is insignificant. There's no such thing as perfect focus when filming 3-dimensional objects anyway...
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Now you're just on a different topic. Arguing why achieving critical focus is necessary for a broadcast application is for another thread. Normal viewing conditions don't exist when sending things out for air. Sure, if I watch an interview on my laptop I won't notice the error like the guy who is watching it on his 70" tv will. I can spend days giving you examples of footage that looked great in a viewfinder and when viewed on a reference monitor when editing, it was clear the focus was on the wrong point, like slightly behind or in front of where it should have been. Now blow that up to a giant hd or uhd screen and its distracting. My point is the focus mag is there for a reason, it may not be necessary for many shooting scenarios, but like I said, in a sit down interview where you may have the lens wide open and your focus is at its most critical, this feature should be a tool and not a hinderance.
 
I have an FS7.

Basically focus mag is a bit of a joke (aka full of artifacts) - personally I find it works best with 'edge enhancement' or whatever its called. On the EVF the FS7 has a switch for this.
 
I've never used Focus Mag, not even once. Peaking is so much more more accurate and easier to use -- and with no extra button pushing or momentary loss of framing in the viewfinder.
 
Doug Jensen said:
I've never used Focus Mag, not even once. Peaking is so much more more accurate and easier to use -- and with no extra button pushing or momentary loss of framing in the viewfinder.
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Interesting. I use focus mag all the time. Find peaking on the FS5 gets me close, but is not as exact as focus mag. I always go just beyond the focus point and then go back. Takes just a moment. Of course, there are times when there is no time for focus mag and I just use peaking. Depends on the situation and what I am shooting.
 
Same on the f5.. focus mag quality is pretty bad.. I used to use the color (Red) peaking on assign .. but changed to what Doug does.. white peaking on the whole time.. LCD EVF.. but would be tempted to shell out the bucks for the new F5/55 EVF if its really amazing ..
 
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