Older t-mount lenses

[wubs]

Is it possible to use a T-mount manual focus lens on my D50?

The lens is a Vivitar 500mm mirror manual focus lens with a preset aperture of f5.6.


I tried (I do have a Nikon T2 adapter), but the shutter won't close. I tried every mode on the camera to no avail.

What am I doing wrong? I'd love to be able to use this again for snapping airplanes at the airshow!

[Esoterra]

sorry for the tangent... but what is a 500mm mirror manual lens? I understand that the focus is manual... but what is this mirror all about? I noticed in the " I'm going to the zoo zoo zoo" thread that some feller was using a Sigma 800mm mirror lens... is this the same thing?

[erichlund]

sorry for the tangent... but what is a 500mm mirror manual lens? I understand that the focus is manual... but what is this mirror all about? I noticed in the " I'm going to the zoo zoo zoo" thread that some feller was using a Sigma 800mm mirror lens... is this the same thing?
One way to make a lens smaller and lighter while still achieving a long focal length is to wrap the light using mirrors. Light enters the front of the lens, bounces off a ring mirror at the rear of the lens, near the camera, is reflected back to a central mirror in the front of the lens, and finally, to the film/sensor through the hole in the ring mirror. I've never used one, but I understand that it's a good idea to have as much as possible in focus with this type of lens, because everything out of focus turns into a ring. Also, these lenses are one focal length and one aperture, usually f8, if I recall correctly.

[DonSchap]

A bit wide, yet lightweight... if anything, the reflector or mirror-lens allows the focal length of the lens to be cut into three parts through a staggered reflection.

11069

Looking at the design of the lens...

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By doing this, the light, instead of directly going down the lens' focal tube (like most lenses do), the physical distance between the front lens and back lens (the one mounted closest to the camera' sensor or 35mm film) can be significantly shortened while still maintaining the distance the light travels through the focusing lens. The unfortunate side-effect of this method is the "loss" of light due to the internal mirrors not being 100% reflective and a lack of corrective lensing elements to control glare and other interfering light frequencies.

The "Filter" (see diagram) in this lens is small (30.5 mm) and removable. It serves a few basic purposes
You may use a UV filter, to reduce UV light
or because the mirror-lens usually is a fixed f/ stop (nominally f/8), the manufacturer will toss in a pair of "neutral density" (NDx2 & NDx4) filters, which you may add to bring the f-stop to f/11 or f/16, depending on which ND filter you use. This allows for a greater DOF and some improved focus.

Because the lens is truly a manual focus, you will normally find that adjusting the focus is much slower and tighter than other lenses, so don't try and use it for "action photography" or you are going to be woefully challenged to the point of utter frustation and futility. This lens is happiest with fixed subjects... and a good, solid tripod.

The lens' front filter ring is normally 72mm on the 500mm, so standard 72mm filters can be used. The special, screw-in 30.5mm rear filters are usually supplied standard with the lens and are extremely hard to replace, if lost. My suggestion is to keep them in their original packaging and place it at the bottom of the 500mm lens' case.

The addition of a focal extender (a gapping tube) can be added to the rear of the lens (usually screwed on between the T-mount and the lens' body) and will normally DOUBLE the focal length (500mm -> 1000mm) in one fixed amount with only about three inches of additional length added to the overall lens length. Unfortunately, it chops off another f-stop or two of light, so daylight is normally a must. Don't try to use a 1.4x or 2x teleconverter with this lens, as I have found that the T-mount adapter does not work with them.(It's a physical design issue... so there really is little you can do about it. I guess that's why the extension tube was thrown in. ) This maybe the same type of issue that WUBS is having with his Nikon camera mount. I can fully attest that the Canon 20D lens mounting has NO issue like what WUBS described with the mirror. Perhaps that's also the DCF difference in distance between the two cameras. Ah ha! :eek: The reasoning begins to gel...

IMO, for the $100 that this lens usually costs, it is a cheap addition to your arsenal and lightweight enough to not be a drag to tote with you. It's kind of a fun lens to mess around with. Also bear in mind, that this 500mm lens translates to a 800mm lens on a Canon digital camera (Rebel, XT, 20D & 30D), because of the DCF (digital cropping factor) of 1.6x. (750mm on Nikon D50 & D70s because of a 1.5x DCF - the back of the lens is a little closer to the sensor.)

Note: This is a fully manual, fixed aperture lens. There will be no electronic aperture data from this lens. All metering will be done as usual, through the glass itself. Forget using a flash, too... because nuclear flash bursts aren't available. LOL. This baby was made to literally go the distance.

[Chris Ross]

Don and erich, thanks! Great info! ok... now off the tangent....

[DonSchap]

I have added some additional information cancerning WUBS original problem. I anxiously invite further speculation concerning this apparent mirror obstruction issue, other than what I have put forth.

Thanks, :D

[DonSchap]

Focusing through relatively 800mm of mirrored optics is no party, believe me. (actually minimum focus dist. = 7 feet!(on a APS-C SLR camera)) There will be no sneaking up on anyone with this puppy.

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For the past few months, I have taken the Vivitar 500mm/1000mm and tried some shots. Each time, despite the sunlight condition, I return home, disappointed :confused: to find the shots hardly focused, frosty and rather difficult to see.

It says it's a fixed f/8 lens... but it acts like a fixed f/11 or worse. All manual focus... it has nothing to correct slight misjudgement of clarity. Taking a 100-yard shot really leaves focusing rather tight... almost impossibly tight. With this lens, an 'infinity focus' is nearly 1000 yards. Focusing in on anything is truly a "touch and go". (Tripod manadatory... because you will never acheive a shutter speed that would "freeze" your subject. Also, you had better nail the tripod down and hope for no wind, either. )

I am half tempted to use a "nuclear" flash bulb to "GET THE SHOT"... due to the poor light response of this lens. Perhaps it really isn't worth the $100 I paid for it. I will try it a couple more times, in the up coming months, before it loses its place on the side of my bag. I guess I'm still looking for the shot that will make it... worthwhile. Any ideas? (Please try to be constructive... and don't say "toss it". I can get that advice anywhere. :rolleyes: )

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Obviously, compared to the Canon EF 500mm f/4L IS USM, they are like day and night... with no moon :eek: (don't laugh, the darn thing costs $5,500... it better deliver the goods.).

If someone has one of these "L"-glass monsters at home... post a shot or two. Please show me what I am missing, because this is painful. :(

[D70FAN]

Focusing through relatively 800mm of mirrored optics is no party, believe me. (actually minimum focus dist. = 7 feet!(on a APS-C SLR camera)) There will be no sneaking up on anyone with this puppy.

11318

For the past few months, I have taken the Vivitar 500mm/1000mm and tried some shots. Each time, despite the sunlight condition, I return home, disappointed :confused: to find the shots hardly focused, frosty and rather difficult to see.

It says it's a fixed f/8 lens... but it acts like a fixed f/11 or worse. All manual focus... it has nothing to correct slight misjudgement of clarity. Taking a 100-yard shot really leaves focusing rather tight... almost impossibly tight. With this lens, an 'infinity focus' is nearly 1000 yards. Focusing in on anything is truly a "touch and go". (Tripod manadatory... because you will never acheive a shutter speed that would "freeze" your subject. Also, you had better nail the tripod down and hope for no wind, either. )

I am half tempted to use a "nuclear" flash bulb to "GET THE SHOT"... due to the poor light response of this lens. Perhaps it really isn't worth the $100 I paid for it. I will try it a couple more times, in the up coming months, before it loses its place on the side of my bag. I guess I'm still looking for the shot that will make it... worthwhile. Any ideas? (Please try to be constructive... and don't say "toss it". I can get that advice anywhere. :rolleyes: )

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_____________________________________
_____________________________________
_____________________________________


Obviously, compared to the Canon EF 500mm f/4L IS USM, they are like day and night... with no moon :eek: (don't laugh, the darn thing costs $5,500... it better deliver the goods.).

If someone has one of these "L"-glass monsters at home... post a shot or two. Please show me what I am missing, because this is painful. :(

If 500mm is your thing... you couda had a "Bigma" (Sigma 50-500 f4-6.3) for less than 20% of the Canon EF 500. Or go for a little less range (80-400) and you could have image stabilization (Sigma OS in this case) for the same price (~$1000).

Mirrored lenses weren't worth a darn on film cameras, why would you think they would be usable on a digital? I always considered them to be a hoax, of sorts, from Vivitar. The couple of times I used this lens on my FE (a manual camera no less) the images were crap.

Dump it, and the frustration... or keep it as a conversation piece... but leave it off of your camera.;)

[DonSchap]

I am toying with the idea of tossing on a Bower 2x Teleconverter ($60) to Canon EF 75~300mm f/4~5.6 III USM ($159) and getting a better stablized autofocus, rather than dorking around with the manual mirror (reflex). I mean, the minimum focal distance is nearly identical and getting some decent long-range zoom at the same time (effectively 240~960mm on the EOS 20D). I get some lens feedback to the camera... (although not the 2x multiplication factor). Admittedly, we're back at f/8~11... which may directly impact the AF at the high end, but even in manual, it just has to be better control than on the Vivitar MF 500mm f/8.

Since I already have these items, I suspect an experiment is in order, here... commensing tomorrow. Thanks George... for stirring the pot. :D

[D70FAN]

I am toying with the idea of tossing on a Bower 2x Teleconverter ($60) to Canon EF 75~300mm f/4~5.6 III USM ($159) and getting a better stablized autofocus, rather than dorking around with the manual mirror (reflex). I mean, the minimum focal distance is nearly identical and getting some decent long-range zoom at the same time (effectively 240~960mm on the EOS 20D). I get some lens feedback to the camera... (although not the 2x multiplication factor). Admittedly, we're back at f/8~11... which may directly impact the AF at the high end, but even in manual, it just has to be better control than on the Vivitar MF 500mm f/8.

Since I already have these items, I suspect an experiment is in order, here... commensing tomorrow. Thanks George... for stirring the pot. :D

Not trying to stir the pot, just pointing out that I gave up on mirrored lenses a long time ago.:)

[DonSchap]

looks like an elephant trunk...

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but, with the Bower MC 2X C/AFI Tele-Converter... the AF is good up to about 200mm (effectively 640mm with the 20D) on the zoom, then it's back to manual focus from about 190~300mm (effectively 608~960mm w/ 20D).

[tjdudley]

I just mounted a Vivatar 400mm lens on my D50 using a Prooptic T-Mount adapter from Adorama. The shutter only worked when the mode dial set to "M" (manual). The pictures were fine.

Jim