Achromat filters

[Ben_Martin_Box]

Hi,

About Achromat filters.

I saw Daniel's scheme to build an achromat filter using binoculars lens.
I noticed that he is mounting the achromat filter between the HV20 and the 35mm DOF adapter.
http://www.jetsetmodels.info/tutorials.htm

All the achromat filter I found in the market seems to be mounted like a regular filter (in front of the 35mm ojective lens).
http://www.enjoyyourcamera.com/Filters-Filter-Adapters/MARUMI-Professional/Achromat:::24_101_110.html?XTCsid=ca67bc677c42b375 46c6e5903ccb7ed3

So I wonder, where should an achromat filter be mounted related to the HV20? Any ideas?

Many thanks!

[mattias]

mounting it behind the adapter helps the camera focus on the ground glass. mounting it in front of the 35mm lens increases the close up range. neither is right nor wrong, just different reasons/results.

/matt

[Ben_Martin_Box]

Many thanks! :)
So, I believe that I can use any Achromat filter (using a step-up ring adapter from 43mm to 52mm) attached to the HV20 and from there attach the 35mm DOF extension tubes, right? :hv20-smilie84:

[tcindie]

Basically.. but keep in mind that acromats, like any lens or filter come in various quality levels.

[Fletch78]

And according to Daniel, the Marumi +5 achromat from enjoyyourcamera is not strong enough for a vignette free image.

I'd go for the Opteka HD2 10x.

[Duke]

Basically.. but keep in mind that acromats, like any lens or filter come in various quality levels.

Using larger lenses 51-55mm in front of the smaller adaptor (43mm) uses the sweet spot on the larger lenses.

Also, two compound lenses does much better than one single lens, which is why Daniel uses two binocular objective lenses face to face. There is almost no fisheye effect that way. They cancel the distortion from each other while magnifying the screen more.

If it wasn't for that distortion you could just zoom in with the HV20's zoom (which in theory goes to .4".)

Duke

[Ben_Martin_Box]

Very cool explanations / tips.

Much appreciated! :hv20-smilie03:

Again, many thanks!!

[Shrigg]

Using larger lenses 51-55mm in front of the smaller adaptor (43mm) uses the sweet spot on the larger lenses.

Also, two compound lenses does much better than one single lens, which is why Daniel uses two binocular objective lenses face to face. There is almost no fisheye effect that way. They cancel the distortion from each other while magnifying the screen more.

If it wasn't for that distortion you could just zoom in with the HV20's zoom (which in theory goes to .4".)

Duke

Which "sweet spot" are you referring to, on the adapted 35mm lens? Will an achromat change the focal length? What about light loss and vignetting?

I am planning a DIY35 static adapter for use with my current TRV900 and future HV20 and want to ensure the best possible image with the least amount of light loss. I have Nikon AI-s lenses 24mm f/2, 50mm f/1.4, 85mm f/1.8 and 135mm f/2.8

Should there be a sticky on achromats? Inquiring minds want to know!!

Thanks,
Shrigg

[musicjules]

Should there be a sticky on achromats? Inquiring minds want to know!!
Thanks,
Shrigg

have a look to all the adapter around here. here is my adapter with daniel's achromat and nikon 1.4 50mm . barely no vigneting with the ZEISS achromat.

http://www.hv20.com/showthread.php?p=48448&posted=1#post48448