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Live Preview on IQ180

Stefan Steib

Stefan Steib

Active member
Variable ND filters are a marketing gag mostly. Get yourself 2 Polarizing filters (any brand- it really does not matter at all -why i´ll explain in a second) screw them together and you have your variable ND filter.
Now there are some problems: as with any filterstacking you´ll loose sharpness, this may not be important if you work only visually.
second you will get color shifts in some oversaturated parts of the image which may look completely different if you remove the filter and third there are interference effects, which may become clearly visible (as a cross in the middle of the image). This means for visual focusing only - maybe ok,
for work with taking images - forget about it.
And if you want to pay several hundred bucks for it then believe the marketing blubber, if you just want to try out buy yourself 2 cheapos from ebay for 20 bucks each(I have 2 x 86mm for my Hartblei 40 with stepdown rings for smaller sizes)
And it does NOT matter which brand you buy, this is physics, which is stronger than marketing..........:cool:

Greetings from Munich
Stefan Steib - HCam.de

PS - found this test comparison image in http://www.videotreffpunkt.com
 
Last edited:
lance_schad

lance_schad

Workshop Member
I just wanted to clarify that this version of the firmware which includes Live View is currently on the IQ180V mount only.

It is my understanding there will be a future release of firmware for the other IQ models that will include this functionality.

Lance
 
Wayne Fox

Wayne Fox

Workshop Member
Stefan Steib said:
Variable ND filters are a marketing gag mostly. Get yourself 2 Polarizing filters (any brand- it really does not matter at all -why i´ll explain in a second) screw them together and you have your variable ND filter.
Now there are some problems: as with any filterstacking you´ll loose sharpness, this may not be important if you work only visually.
second you will get color shifts in some oversaturated parts of the image which may look completely different if you remove the filter and third there are interference effects, which may become clearly visible (as a cross in the middle of the image). This means for visual focusing only - maybe ok,
for work with taking images - forget about it.
And if you want to pay several hundred bucks for it then believe the marketing blubber, if you just want to try out buy yourself 2 cheapos from ebay for 20 bucks each(I have 2 x 86mm for my Hartblei 40 with stepdown rings for smaller sizes)
And it does NOT matter which brand you buy, this is physics, which is stronger than marketing..........:cool:

Greetings from Munich
Stefan Steib - HCam.de

PS - found this test comparison image in http://www.videotreffpunkt.com
Click to expand...
While I agree with most of what you say, I would suggest that perhaps the heliopan filters are not "exactly" two polarizers. It supposedly can be dialed down to a single stop ... two polarizers stacked will create more ND than that. How they do this I'm not sure, because my singh-ray minimum is 2 stops. Also, because of the way they are made the two elements are much closer together than two polarizers, helping with their optical quality.

Of course, in this discussion we aren't talking about taking pictures through the polarizers, we're talking about away to vary the light when using live view on a digital back. A variable ND would make that task immensely easier. In this case, I'd agree ... two cheap polarizers should work just fine for that.
 
Stefan Steib

Stefan Steib

Active member
Wayne

I can only guess, but maybe they have combined a linear and a circular Polarizer ? and probably making the glass thinner than usal could also help,as well as you mentioned keeping the filters in closest possible distance.

But optically (and financially!) a normal ND will be better.

But to get back to the live preview task - If Phase has really managed to get this working in daylight - without shutter - RESPECT !
Then this is a major step forward !!!

regards
Stefan
 
kdphotography

kdphotography

Well-known member
Stefan,

My understanding of the "variable" ND filters is that a linear and circular polarizer are sandwiched together.

ken
 
jotloob

jotloob

Subscriber Member
Stefan Steib said:
. . . . . .
But to get back to the live preview task - If Phase has really managed to get this working in daylight - without shutter - RESPECT !
Then this is a major step forward !!!
regards
Stefan
Click to expand...
. . . then forget about a bulky and delicate sliding adapter .
This is the future . Great , just great :thumbup:.
The IQ160 comes into my dreams again .
 
Stefan Steib

Stefan Steib

Active member
@Graham
these are Videopeople- they tick different, they have fixed timings you remember ?
@Jürgen
I am pretty sure that we are still faster with a motorized slide to the left (7 Sec.) if you need to apply and remove an ND filter. Further- how much power will it consume ? If I were a battery maker, I´d stock up on Phase batteries.

just a thought........:)

Stefan
 
Jack

Jack

Sr. Administrator
Staff member
Just loaded it on my IQ180 and gave it a quick spin on my tech camera --- I am happy to report Live View works as advertised. It's a long way from perfect, but far better than I had assumed it would be. Also, on my tech cam it was fully usable at f8 and f11 *without* an ND filter -- note this was in dimmer, early AM light, so maybe it will be problematic in bright Sun. Of course you loose the paper thin DoF of f4 or less for critical focus, but then I carry ND's with me anyway for when that's needed.

Pretty cool overall and gets a solid :thumbs: from me!
 
R

rupho

New member
Jack how did you download the new firmware
Can't seem to find it at P1
are you are beta tester?

Jack Flesher said:
Just loaded it on my IQ180 and gave it a quick spin on my tech camera --- I am happy to report Live View works as advertised. It's a long way from perfect, but far better than I had assumed it would be. Also, on my tech cam it was fully usable at f8 and f11 *without* an ND filter -- note this was in dimmer, early AM light, so maybe it will be problematic in bright Sun. Of course you loose the paper thin DoF of f4 or less for critical focus, but then I carry ND's with me anyway for when that's needed.

Pretty cool overall and gets a solid :thumbs: from me!
Click to expand...
 
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