adapter for Nikon lenses
 

Hello,
I have been looking for a way to adapt Nikon lenses to my HV20. Several 35 mm adapters are available but there main focus is to get a shallow DOF. That is exactly what i don't want. Does something exist like the EF adapter for the XL1, which does not reduce DOF (that much)?
Rob

Nobody with a suggestion. That means that my question was
1 brilliant
2 very unclever
Which of the alternatives is true?

Rob.


What special thing do you want the camera to do for you?

If it is extend the optical range of your camera furthur into extreme wide-angle or telephoto views, you are better off buying in wide angle and telephoto adaptor lenses to go on front.

You can shoot aerial image through Nikons by taking the groundglass out of 35mm adaptors but you give yourself a big problem with vignette on wide lenses and the telephoto lenses, which leaves you with about the same range of views that your camera's own lens can provide and a softer image.

I use a Sigma for Nikon 50mm to 500m f4 - f6.3 zoom for ground-to-air vision of aircraft but because of the wider 35mm field-of-view I gain only about 30% more at the telephoto end over what I can get with the camcorder's own zoom lens.

I want to film birds. Bought myself a 2.0 times teleconverter, but it does only 1.5. But neither 2.0 times would be enough. I need more tele. That's why I am searching for a solution. A HD camera with interchangable lenses is beyond my possibilities. I was thinking of purchasing a HDSLR to have an affordable solution (I have a series of NIKON lenses in the drawer), but I read a lot of BUT's on the net. Besides I really love my HV20 and would want to use that.

Could you explain me some things? Any help I would appreciate.
1 What exactly does a 35 mm (DOF) adapter do to the basic image of a HV20?
2 How would it effect the image from a, say, 500 mm tele (I mean without removing the groundglass (what is groundglas?)? And what would be the focal length of such a lens in combination with the adapter and the HV20?
3 Is there any other affordable alternative way to get what I want?

If you want to home-build something, start with these parts and dimensions as a rough tryout. Fasten the camera onto a plank of plywood. You may need to add spacers between the plywood and camera base to raise it up a bit.

Make some vee blocks to rest the Nikon lens in so that its optical centre is exactly the same height above the playwood as the camera optical centre.


Camera. fitted with a 7+ achromatic dioptre (close-up lens) to suit front filter thread mount. 10+ may even work.

Nikon telephoto lens. Widest aperture you can get. Its probably going to be have to about f4 and no higher number. F2.8 better.

Set camera to manual focus. Open iris of Nikon lens to widest.

Once you have got the optical centres lined up, place the lens so that the mount face or flange is about 185mm from the front of the close-up lens on the front of your camera. Get the back of the Nikon lens lined up by using the zoom on your camcorder in wide view, then zoom in all the way. If you are lucky, the zoom-in will take your cmaera view inside the vignette of the Nikon lens.

You should be able to see an image in the LCD screen. Slide the lens closer or furthur away from the camera. This should bring it into rough sharp focus. The image will be upside-down. This should give you some idea if you are going to be able to make something workable.

You may be able to get hold of some lens extention tubes with Nikon mount on front and step-up adaptors to make it fit your camera. This is how some builders make their 35mm adaptors with a groundglass in them.

Look up Oscar Spier in dvinfo search. I think he makes a kit or will reference one which is basically a tube with mount for camera on one end, close-up lens and Nikon mount on the other with a groundglass inside. You may be able to order the parts without asking for the groundglass itself.

The very simple 35mm adaptors do not return the image to correct upright position so you will have to learn to shoot with the image upside-down or turn the camera upside-down. The LCD will still show an image which is upside-down to look at.

Some cameras can be tricked by placing a magnet close to the LCD screen hinge into making the LCD image flip upright.

Thanks for the recommendations. Before I start building anything myself (I am not very skilled technically) I'ld like to ask some more questions.

The main thing that puzzles me in both alternative possiblities (work with a 35 mm adapter on the HV20 or buy a GH1 and adapt my Nikon lenses to it) is that I will have to shallow DOF when filming. The DOF I will have with a HDSLR I can estimate roughly from other SLR's with my Nikon lenses (though this will also depend on sensor size), but the DOF I will have after attaching a 35 mm DOF adapter on my HV20 together with the nikon lenses I can't ill this be in the same order?

I have tried the set up as described with 3 tiffen close up lenses (together 7+) and that seems promising. But building an adapter is not really for me. I am not very handy. I suppose I would need a series of Nikon extension tubes, a quality close up lens (I gues 10+ or even more to reduce the length of the adapter) and a set of rings without glass. The most difficult thing must be how to connect a ring with a thread to a Nikon extension tube.
And what else would I need?

I suppose that somebody has made such an extension tube with a tread on it (instead of using a glue or something). Can I buy it and where, from who? Preferably I would buy a complete adapter without groundglass. It must be a sturdy one, because I will hang my HV20 on the adapter without support.

The cheapest answer, is a 3x teleconverter like the Raynox.

I'm shooting birds with a HF100 + 1.5x or 2.2x. My HF100 has a longer tele than your HV20, so a 1.5 gives me effective 750mm and 2.2x gives me about 1100mm.

With the 2.2x Raynox, it starts to get difficult to find my subject. Sometimes I zoom out and back in a few times. I gave up on warblers, shorebirds are easier.

I'm hoping the next Canon xxD\60D DSLR will have 720p and manual control. I'm already using Canon DSLR's for my birding photography.

Diy
 

Daniel's GG-Holders for 35mm DOF Adapters or... Wait til July and order one from index

Daniel Schweinert from jetsetmodels was replying to my message with:

thanks for your interest but I don't produce complete adapters anymore.
....
You have to build it yourself.
....
Never done a dof adapter without ground glass before so I really don't know what has to be changed but usually that makes no sense if you don't have a ground glass. I can imagine that if you don't have a ground glass you will not be able to get a picture that will cover the ccd area of your HV20.

Regarding the last sentence, I wonder if he has a point or not. As mentioned, I tried the set up with HV20 - 7+close ups - Nikon lens and I had an image on the lcd from the hv20. I am not good in optics and I would like to know what kind of image this is. In case of a DOF adapter with gg it is easy to understand, because the hv20 can focus on the gg, but in an adapter without gg, what forms the image? Where is the focus plane or point? Please explain.

Where the groundglass place is in the 35mm adaptor, a sharp image falls from the Nikon lens on front. When the videocamera lens is focussed sharp on the groundglass, the image projected onto the groundglass is seen by the videocamera.

When these two things happen, it is possible for the groundglass to be removed. The videocamera will now see the same image but depth of field will be deeper. What the videocamera now sees is called "aerial image"

If the exit pupil on back of the Nikon lens is small, the videocamera may only see a small round image. If the exit pupil on the Nikon lens is about 20mm wide, the videocamera should be able to see through the Nikon lens without the image corners being cut off.

Daniel's first adaptor I think was made up with extention tubes and smaller spacers to adjust the length. On front was a stil-camera lens mount. On back was a step-up ring to match the filter thread on the camcorder. These are not hard to put together. The harest job is to find the parts.

If you measure from flange face on the Nikon lens to front face of camcorder, when you get a sharp image on your test rig, that is how long the adaptor tube and the extra spacer rings has to be.

Rob,

A DOF adapter is not really what you want, with or without the GG.

Trying to shoot thru an SLR lens won't work either. Try this to convince yourself, mount the lens on a tripod and focus on a distant object. Now simply try to look thru the lens and see if you get clear image or not - you won't unless you're about 1 foot away. Try it with your camcorder as well.

That's why we cannot use an SLR lens as a tele/spotting scope without a special adapter/eyepiece like this. I have this, and I know it works. There are similar adapters for adapters F-mount lens. Adapting a telescope eyepiece would work as well.

By doing this, you're in effect digiscoping (you can look that up), shooting images or video thru a scope. I know a few birders who do this.

Here's a link for the Nikon adapter Nikon Lens Scope Converter

OK thanks Bob, those are encouraging words. I just wished that others (Kin Lau) would have comments in the same direction. Would you disagree with him?

I will try and get some parts together. I won't die from it.

Rob.


Neither Kin or I are right or wrong on this.

The dioptres he linked to are near enough to the same thing, a close-up attachment to enable the human eyeball to view through a stills camera lens or telescope with an optical or erecting flip element.

Videocameras require a larger exit pupil to be able to see through without vignetting (cutting the corners off or making a circular dark border around the image).

For the original non-flipped AGUS35 I built, to keep things compact, I chased down a telescope eyepiece, in that instance an unbranded OEM 50mm eyepiece for Tasco scopes which bore the model number on the box of SW5042.

The effective exit pupil of this optic was 44mm. I made my own barrel for the optics with the approporiate threads cut either end and also did likewise for a night-vision scope.

For the PD150 camera zoomed right in, I got a better outcome when I reversed it so that the "eye" end was closer to the groundglass and the "telescope" end was as close to the camera. In this arrangement the third biconvex element in the eyepiece changed function to becoming a condenser lens. It had a very extreme magnification of about 20+ and sat only about 12mm - 18mm from the groundglass. It also barely covered the 24mm motion picture frame size.

If you search YouTube for DARANGULAFILM, then scroll the clip list to find Kim Bettenay "My Time Again", that little music clip was shot with that rig, as was another title "The Sock".

There was a special larger diameter scope eyepiece which was already fitted as a telescope adaptor for 35mm still cameras and videocameras. It did not meet what I wanted so I went my own way with the SW5042.

You have the proof of what can be done already on your workbench. If you have a camera or lens repair shop anywhere near, go and see if they have any extention tubes, Nikon mounts and adaptor rings you could stack in their secondhand parts bin.

Wayne Kinney (SGPro/SGBlade) and Dennis Woods (Cinevate/Brevis) may still have some of the more powerful achromats (10+ or thereabouts) they used in their earlier non-flip adaptors they might be able to sell. The back of Nikon lens to front of videocamera distance with a 10+ may be in the ballpark of about 3.5" to 4.0".

The stronger the achromat the shorter the distance between Nikon lens and videocamera but other issues can emerge like corners going a little softer or stretchy in the radial direction and associated CA (chromatic abberation) which is a sort of rainbow effect you will already be seeing with your stack of HOYA single element lenses.

There used to be a HOYA 10+ achromat discussed here which was 58mm diameter filter thread with smaller exit pupil of about 52mm (I think from bad memory here). It was borderline for adaptors but might suit your camera if it has a front element diameter of no more than about 52mm. There might be a few on eBay.

If you can't find enough threaded spacer rings and extention tubes, there is always my trick of using PVC plumbers pipe and glue. Paint it with wroughtiron black and the average punter doesn't know the difference. Carpet roll or butcher's paper roll centre cores may be another raw material you can try.

My very first proving adaptor was a Pringles can after I ate the crisps, two sock cuffs, (heels had worn out) rolled up to hold the Nikon lens in one end and the dioptre in the other with a hand ground microscope slide stuffed through a slot in the middle for a groundglass. It was surprisingly good in a sandpapery textured sort of way. For your aerial image application you would not use the microscope slide.

Don't give up just yet.

I forgot about this clip. Most of it was shot in aerial image mode through the flip version of my home-made AGUS35 adaptor - no groundglass.

YouTube - TIGER BALM

The stills lens on front was a Sigma for Nikon 50mm - 500mm f4 - f6.3. The camera was a Sony HVR-Z1P.

There is a considerable amount of overlap between the bare camera lens sees and what the long lens on the adaptor sees. The overlap cuts out at about 350mm on the Sigma lens.

You will observe an iris blades vignette in the overhead ground-to-airs. The Murrayfield sky is very hard due to reflection from nearby lakes and white sandy ground and I had closed the Sigma iris a bit. The adaptor was off-centre because I had given it a bit of a thump transporting it.

The Raynox or similar teleconverter probably remains the best turnkey option for you. For sighting, another cheap handycam mounted in tandem with your long camera on a bar fastened to your tripod would work if you have trouble aquiring your subject though a long lens. You harmonise the sighting camera at its longest zoom setting to the view of your long camera by moving it on the bar until both views are centred to each other then lock both cameras down to the bar.

I found that with practice, using the left eye for sighting and the right eye to the viewfinder cup I could do nearly as well.