Diopter Questions

I bought a set of Tiffen +1, +2, +4 diopters. I'd like to put them in my flip filter holder. Is there some special technique to get the glass out other than cutting the metal frame ?

Also, which diopters are you guys using ? I experimented with the +4 and my flat port in the bathtub. I was expecting more magnification and the flat port alone let me zoom more before loosing focus.

Rough estimates comparing flat port vs. +4, both zoomed just before loosing focus, the +4 was around 1.5 larger.

Wondering if I should get a stronger diopter. A +5 and +10 is available. My flat port doesn't have enough room to stack diopters.

Hi Ron, from using them on stills i can tell you that your minimum focus distance definitely will get you closer with a diopter. A +4 is pretty strong, and it will definitely limit your depth of field quite a bit. You should be able to fill the frame with a nudi head with that.

You are using a TRV 900 or 950 if i recall correctly?

When getting into that super macro stuff i would definitely suggest a small tripod or something to steady the camera, you will find the shakiness is really magnified as well.

To get it out of the frame have a look at one side of the frame for a c clamp looking thing, that is usually how they are held on, if you can get that out then you are in business...but...i haven't done it myself...

Am thinking of having a look today though, so i might get back to you later. Or PM Wagsy, i know he has done it

Mike

Ron

It really depends on what shot you want. With my PD170 and a +7, I could get a pygmy seahorse's upper torso in full frame. I've tried +11, stacked +4 and +7 both century optics achromatic diopters, with u/w magnification and the gap inside my flatport, well it's just too close and the lighting is affected by the housing. I'd say stick with the +4 and experiment with a teleconverter.

I want to start doing macro work and need something stronger than just my flat port. I haven't had any luck with my multiport macro lens from Gates (made by Inon ?). The usable depth of field is way way too small and it didn't enlarge as much as I would like.

I'm not sure if I'm doing something wrong, or my expectations were too high.

Since diopters are cheap and people here are recommending them, I bought the Tiffen set.

Here are still clips with flat port and +4 diopter and just flat port.

Mike, yes, I have a Sony TRV900 and Gates housing.

Dru, what is a teleconverter ?

Hey Ron,

One of the problems with the Gates and 900/950 is you don't get full zoom capability without losing focus. That always bugged me....

Now i do have it with the Phenom and my macro stuff has skyrocketed!

Not really sure what other options you have other than buying the Fathoms imaging macro port... expensive....or perhaps a higher numbered diopter

A teleconverter is something that fits over the lens, like an extension tube. It narrows the field of view. You won't have room for it in your housing...

Here are 2 more video still captures:

This is with my Gates Multiport Macro lens, which I believe is made by Inon. My camcorder lens is about 3 inches away, zoomed as much as possible before blurring. With this lens my camcorder lens needs to be 2 or 4inches away from the subject. Any more or less and the picture blurs.

This is just the flatport.

I received the following response on the Yahoo board. It explains a lot and I think a +2 diopter may work better for me.

An interesting visual record of diopter experiments that illustrates

what a diopter really does and doesn't can be found at

<http://home.sprintmail.com/~awiner/diopters.html>

These experiments were done in air rather than in water, but the

principles are the same, only the numbers are different in water. The

bottom line: a diopter doesn't really make the image larger than it

would be if you were to put the camera next to the subject. But it

does allow you to create a reasonable working distance between the

camera and the subject and still zoom enough that the image is as large

as if you were right on top of the subject, more or less, depending on

the diopter. But I think the web site explains the basic idea and the

effect on focus range and depth of field pretty well.

Happy New Year!

John F. Williams

In basic terms, a diopter reduces the minimum focus distance in strengths of 1/ +n where n = diopter strength (eg +1, +2 etc). So it allows you to use maximum zoom and still focus closer than without a diopter, thus enlarging the subject, but also reducing DOF. Just as telephoto lenses decrease DOF by moving closer to the subject, with a diopter, you're closer so the DOF is shorter. I'll skip the math since that requires thinking on my part.

If your minimum focus distance is eg 1m. Then a +4 diopter will allow you to go to 1/4 to the subject etc, thus enlarging the subject.

I was testing the A1 with a +7 diopter and using telemacro mode, I could focus on a subject that was 1.2cm wide in full frame. Of course DOF was pretty thin. And with the magnification of water, I'd say it'd be under 1cm. Steady mode was useless so the housing will have to be spot on neutral or on a tripod to get a steady shot.

Above water my camera will focus as close as I can put the camera to the subject. I put a +2 I had sitting around on it but didn't get any noticable results. I can put it right up against something at full wide, and if there's light to see I can manually focus on it without any extension lenses. Maybe underwater it will be different. I haven't tried any close ups there. Any ideas?

That's the common misconception of focusing on subjects u/w. Many think there isn't any difference at full wide focal length. Problem is your subject may not let you get that close. So you usually are a bit back and zooming in. At full zoom, the minimum focusing distance(mfd) is usually a bit back, eg the A1 is 483mm in telemacro mode. So the FOV is about 500mm. By using a teleconverter, you can get 2x (or whatever multiplier effect) zoom in, but your mfd increases. A diopter will let you focus closer, thus making the subject larger while maintaining a working distance between lens and subject.

Thanks. I did notice that effect when zooming in. The problem I've had when using other diopters is that the focal point moves very close to the camera and then I have the same issue of putting the housing against the subject and squashing him Maybe a +4 is less than what I used in the past. How far away can you be from a subject with a +4?

Hi Ron, i took apart a diopter today.

Pretty easy actually. It has a ring on the front with two notches on it. The best tool would be some sort of caliper thing to insert in and unscrew the ring. I don't have that tool so just used an oring pick and a small flat screwdriver....

M

Hi Ron, i took apart a diopter today.

 

Pretty easy actually.  It has a ring on the front with two notches on it.  The best tool would be some sort of caliper thing to insert in and unscrew the ring.  I don't have that tool so just used an oring pick and a small flat screwdriver....

 

M

<{POST_SNAPBACK}>

Either I'm an idiot or my diopter is different than yours. Mine is a Tiffen....

One of my arrogant engineers that works for me kept telling me I was making "id-ten-t" mistakes with the new software. After about a week of me asking what "id-ten-t" was he said you are spelling it wrong, it's spelled "id-10-t".....IDIOT

Ha ha ha ha

Mine is Vivitar

My suggestion is give diopter to engineer and have him do it for free and tell him that is what he gets for calling you an idiot!

Ron

Tiffen filters should use the same removable rings. I think there are only 4 real manufacturers of these rings so they are pretty much the same. There are some which use the snap on method but those guys are the generic filter makers which make cheap filters under different brands. Just looking in the front (female grooves) side on the inside on the elements and you should see those tiny notches. BE careful not to scratch the element while attempting extrication.