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hvx200 focus question

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hvx200 focus question

New postby Mo Zee on Thu Dec 27, 2007 1:24 am

Im using- hvx200, brevis, 1.4 50mm nikkor

I decided to test my setup using an hd monitor, and I noticed something I couldn't really see on the on cam lcd-

I'll try to explain this as clear as I can. When focusing the hvx on the grain, It seems to be in focus on two occasions, 1 focus number apart on the hvx. One is the grain, but when I shift focus slightly, the grains form a concentric ring pattern. Both look in focus, however the grains look sharper when the pattern isn't seen. Now, where should I set focus on?
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New postby Jon Wolding on Thu Dec 27, 2007 1:55 am

Focus on the grain, not the concentric rings.
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New postby Mo Zee on Sat Dec 29, 2007 7:28 pm

thanks
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back focus with the hvx

New postby Richard Hosking on Sat Jan 12, 2008 9:44 am

I've found a good reliable way to make sure the back focus is right. I always tape the focus and zoom rings so they cannot move.(of course). The zoom ring is normally 18.5mm on my HVX, and I focus on the grain of the imaging element and tape the focus ring. I start the brevis, get a focus daisy wheel test chart (one is attached to the back of my slate - you can download them from the net) and get the best possible focus on the chart, normally using a 50mm lens, filling the frame with the chart. Then I hit the auto focus button. (temporarily) This pops in the last little bit of focus, if I've moved the focus slightly in taping the focus ring, it fixes that. You see the lines resolve just a little more. It is also a great way to check that things haven't changed through the day. (they can, with varying temperatures) You can see differences clearly on the LCD. I also use the chart for critical focus checking all the time.
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New postby Jon Wolding on Sat Jan 12, 2008 5:28 pm

I use tape, too. I also use a lighter-colored tape so I can write the MF and Z numbers on it.
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Re: back focus with the hvx

New postby Viet Tran on Thu Mar 20, 2008 9:30 pm

Hi Richard,
I have question about your technique...you said:

"I start the brevis, get a focus daisy wheel test chart (one is attached to the back of my slate - you can download them from the net) and get the best possible focus on the chart, normally using a 50mm lens, filling the frame with the chart. Then I hit the auto focus button. (temporarily) This pops in the last little bit of focus, if I've moved the focus slightly in taping the focus ring, it fixes that..."

My question is: if you have the lens attached to the Brevis and the camera focus rings are taped, and then you press the autofocus button to resolve the last bit of focus,... isn't that useless since that focus is only made for the currently mounted lens at that particular distance from your camera? If you decide to focus on an object at different distance from your camera with the same lens, wouldn't it be off? AND if you decided to change lenses, wouldn't that be off too? Thanks for your reply in advance.

Viet :?:
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New postby Jon Wolding on Thu Mar 20, 2008 10:23 pm

The autofocus would find the sharpest state of whatever is focused or unfocused on the imaging element.
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New postby Richard Hosking on Sun Mar 23, 2008 11:34 pm

I use this technique for getting the back focus exactly right. Lens focus is a different issue.
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New postby Mo Zee on Tue Mar 25, 2008 8:53 am

I have another question- Is f4.0 the widest opening to get correct backfocus? Was gonna test this but I can't find my focus chart...
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New postby Jon Wolding on Wed Mar 26, 2008 8:33 pm

For back focus:

I typically point the camera on a brightly-lit place, stop down the taking lens to f16, adjust the zoom level until I don't see the frame, focus on the grain, then gaffer tape down the focus/zoom rings and write the MF/Z numbers on the tape.
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No focus number

New postby Max De Ponti on Thu Mar 27, 2008 5:34 am

Hi guys,

I just wanted to ask you the reason why I can read the number of the zoom value, but not the number of the focus, 'cause it just reads "MF MACRO".
Is that because the European version of the HVX doesn't show the numbers when in macro mode or is there a way to activate it?
Thanks in advance,

Max
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New postby Jon Wolding on Thu Mar 27, 2008 8:28 am

Hmm... can you take a photo of the menu showing the options for focus display?

The only thing that would suck about not having a precise number for focus would be the lack of a quick reference for back focus assurance. Setting up the back focus wouldn't change a bit.
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New postby Max De Ponti on Thu Mar 27, 2008 4:34 pm

Hi Jon, I don't have my camera with me in this moment, but it works absolutely the same for back focus. I just think it could be a good reference to have numbers like you all have. When I put on the achromat it automatically switch to "MF MACRO" and the numbers for focus disappear.
Just wanted to know if it was normal...
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New postby Jon Wolding on Thu Mar 27, 2008 10:03 pm

Max De Ponti wrote:Hi Jon, I don't have my camera with me in this moment, but it works absolutely the same for back focus. I just think it could be a good reference to have numbers like you all have. When I put on the achromat it automatically switch to "MF MACRO" and the numbers for focus disappear.
Just wanted to know if it was normal...


Look at this menu setting...

7. DISPLAY SETUP > ZOOM-FOCUS > NUMBER


Is YOUR camera set to "NUMBER," "mm/feet" or "mm/m"?
Set it to NUMBER. And turn off any switch or setting labeled AUTO. And flip the focus gear drive (under the lens on the front of the camera body) off (MANUAL, not SERVO).

Now tell me if your LCD still displays "MF MACRO" instead of "MF ##".
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New postby Max De Ponti on Fri Mar 28, 2008 6:07 am

Thank you Jon, I solved the problem. My focus was set to mm/m and under 1m was switching to MF MACRO. Now that I set it to number i have always an indication...
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New postby Mo Zee on Fri Mar 28, 2008 9:05 pm

Hi Jon. I was asking about the widest recommended opening after setting back focus. I remember reading somewhere that anything wider than f4.0 would be out of focus but I couldn't find the article or thread anymore...
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New postby Jon Wolding on Fri Mar 28, 2008 10:26 pm

I shoot with the HVX wide open, stopped to f11, and everywhere in between.

Sure, f4 might be the sharpest... but if you can't see anything, then it doesn't matter.
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