mark_michaelson

<p>No need for messy powdered graphite. Loosen the clamp, tilt the ball over into the slot, get your #2 pencil and start shading the surface of the ball. Coat the whole ball. No mess.</p>

<p>12 years since my last response above; there's a fellow online selling adaptors for the c3 Cintar to E-mount and M43 mount mirrorless digital cameras. He is enthusiastic. Pay him a visit and keep that lens in service.</p>

<p>Adobe "Camera Raw 8.5" update for Photoshop and Photoshop Elements will accommodate in-camera raw files from Sony Alpha 7. I updated my PSE 12 today for my recent *bay purchase of a broken "parts-only" A7. The seller warns: "Don't put an aftermarket soft release on your A7". The shutter button stem is extremely thin plastic. If the soft release snags on your jacket lapel or anything else, it will snap the button stem like a twig. I can attest that the broken shutter button stem is extremely thin dia. My recently acquired "broken" A7 (otherwise flawless) is currently being triggered by the remote shutter release app via laptop PC. Fortunately, the optional 2-battery grip has a an additional shutter button, so I ordered one tonite.</p><div></div>

A little late for this offering, but hey... maybe somebody will stumble upon it in a search - like I did.

 

Why would you even worry about the diffraction limit at all - unless the diffraction-degraded resolution of the lens approached the limited resolving power of the film? 50-100 line pairs per mm is about the practical limit for color negative film. Stop right down to an aperture a = f/22.6 (61 lp/mm)if you want.

 

One would think that the diffraction limit (as a function of f/a)changes with a change in focal length, because the same f/a at a longer focal length needs a larger aperture (a) - and we know that the diffraction limit is inversely proportional to a. A longer lens at the same f/a ought to have a larger aperture, and subsequently, a smaller diffraction limit, right? This is true. However, the diffraction limit as a function of aperture is actually expressed as an angle. When that angle is projected onto film with a longer lens, the lens is further away from the film (longer focal length), and the distance that angle covers on the film increases proportionally with the focal length.

 

So the diffraction limit, expressed as the distance on the film subtended by the diffraction limit angle (lp/mm), is effectively constant at constant f/a, regardless of focal length.

Don't forget the Koni Omega. 6x7 RF with interchangeable lenses, and multiple film backs (M & 200). Sharp Hexanon lenses. $100 on *bay.

It's 5 years now since the post (plus or minus), and film is still here.

Why would anybody place a Miranda SLR on the mantle? It's much handier to keep it loaded in the glovebox.

 

I'd shoot the Pan, and develop it for fun. I bought a Kodak Tourist a couple years ago that had a roll of exposed 620 B&W in it. Developed it in microdol-x, and they turned out just great. Must have been 30 years after exposure, based on the subjects.

Spelling 'scused.

 

I think the current crop of 1/2 frame digital cameras has a lot in common with the 110 film crowd. Same limitations with bokeh, etc. I don't recall the debates of 35mm vs. 110 image size in the seventies though. Did it ever happen?

 

126? I loved my 126 Kodak (with spring loaded auto-winder), and recently scanned my pre-pubescent negs from the early seventies. Sharp as a tack.

 

My opinion is that if the 1/2 frame digital cams can currently dominate the market - then the time is NOW for 110 to come back!

 

What about the Kodak disk camera? Now that's a format!!!

Charlie, typically the science fair is aimed at displaying the application of the scientific method - and not your ability to build something neat. Observation, hypothesis, prediction, experiment...

 

You might get by observing that 35mm camera bodies are complicated mechanisms, that building 35mm camera bodies is difficult at best. Predict that it is unlikely that you can build an acceptable 35mm camera body from scratch. Then attempt to build a 35mm camera body - to prove that your hypothesis is correct.

 

I've judged a few science fairs, and the neatest projects turned out the nicest products - but didn't fulfill the objective of using the scientific method.

 

Good Luck.

I understood your question from the start of the thread - and my mindreader is the old Model 1500. You have to know how to tune it. I recommend foregoing the oatmeal box, and using an already constructed 35mm camera body. Simply remove the lens, and replace it with a piece of foil equipped with a pinhole. Handling the film in total darkness, processing the film, etc., distracts from the pinhole experience. My favorite pinhole camera is an Argus C3, but any camera body can be used. Can be picked up for about $5 online.

But seriously, you can achieve the diffractive soft result you are looking for with a piece of aluminum foil, and a punched hole of approximately 0.3 mm diameter (about the diameter of a "pin").

 

Center the hole and indent the foil as far as possible such that it doesn't interfere with the mirror. Thinning the foil by hammering it can improve the sharpness of the pinhole. I'm not familiar with the D30, so I don't know if it will fire without a lens. I doubt that it will. Just mash the foil as close to the lens as possible.

 

On a similar note, I'm looking for a hand-starting crank and GM-Electronic Controls Module (ECM)-compatible magneto for a 1998 GMC Sierra pickup with a 5.0 liter V8 (Throttle Body Injection) - I don't want to adversely affect the emmissions computer, but I want to be able to hand-crank start the truck if the battery is dead.

The lens gets in the way.

 

Presumably, you could remove it (and some of the lens mount) and get your pinhole closer to the sensor. 110 pinhole never developed a devoted following either - for the same reasons. 35mm pinhole is one of those things you do once or twice with aluminum foil and the Argus C3 to test the dubious theory of the rectilinear property of light. I recommend spending the $2 on a can of oatmeal, and another $50,000 for a high quality medium format digital back, to make the leap to digital pinhole. In this manner, you can go digital without incurring the exhorbitant cost of a lens.

It's not just the temperature, it's the TIME and the TEMPERATURE. The short duration at elevated temperature should have no significant effect on your film. In the temperature domain, the temperature excursion was relatively low. For the purposes of accellerated aging, ABSOLUTE temperature is the parameter with which we are concerned. Add 460 Deg to the Farenheit value to obtain absolute temp in Degrees Rankine. Add 273 Deg to the Celsius temp to obtain absolute temp in Degrees Kelvin. 95 DegF is 555 DegR (degrees Rankine - absolute temp scale). Compare that number to Fuji's recommended 50 DegF (510 DegR). 555 DegR is only about 110 percent of 510 DegR.

 

I suspect that if you look closer at the Fuji recommendations, the 50 DegF value refers to STORAGE temperature. Storage for long periods of time at elevated temperatures can significantly shorten the life of film.

 

You should, by the way, apply the time and temperature accellerated-aging philosophy to ALL important elastomers - including camera body components. Light seals and bumpers turn to goo due to time and temperature. 30-40 years at normal room temps turns seals and bumpers to goo. Rubber bumpers in Konica Autoreflex models get sticky and can be found online for cheap (and easily fixed). They'd last longer if stored in a ziplock bag in the freezer. They'd goo faster if stored in the attic, or in the car's glovebox.

 

Store in a cool, dry place.

He bought the car and paid for it. The car is not in his hands yet, and he cannot possibly shoot the car himself. Your description of the car, text and photos, could be assumed by a reasonable person to go with the car as part of the deal. Would you sue him for plagiarism (sp?) for translating your description of the auto into German for the listing on eBAY Germany? On the other hand, would you pay him a fee for having pics of (now) HIS car on your website?

 

While you probably would be able to ruin his auction by getting eBAY involved, your conduct would be considered most unsportsman-like by even the most casual observer.

One should not be camping unless heavily armed in bear country.

 

Your personal safety should be a higher priority to you, than any of the currently popular ideas regarding the "rights" or sanctity of non-human forms of animal life.

 

If it isn't, and you choose to camp unarmed in bear country, then you have volunteered to be considered as prey.

By my rough calculations, to obtain the background out-of-focus effect of an unstopped 50mm lens focused on a subject at 3.7 meters, with a background 10 meters behind the subject (background image forming 0.50mm in front of the film plane),...

 

...on a half-frame camera: One would need a very fast 1000mm unstopped lens at a subject distance of 148 meters to obtain the same crop and selective focus (background image forming 0.48mm in front of the film plane).

 

Or if the thought of using the 50mm 1.4 on a 35mm film camera was still unbearable, one could move the subject much further from the background, to keep the background image from forming too close to the film plane.

Okay, here's a first stab at it:

 

135mm lens, image size equal to full. Object 2000mm from lens. Subject has an exceedingly long nose for the purposes of our exercise - say 100mm.

 

The Lens Formula:

Image distance s' = (s x f)/(s-f), where s is the subject distance, and f is the focal length of the lens.

 

For the subject's eyes, at s=2 meters, the image is formed at distance

s'=(2000 x 135)/(2000-135), or 144.7mm behind the lens.

 

For the subject's nose, at s=1.9 meters, the image is formed at distance

s'=(1900 x 135)/(1900-135), or 145.3mm behind the lens.

 

Of course we are focused on the subject's eyes, and the nose will be out of focus, as it's image has formed 0.6 mm behind the film plane.

 

We take the lens off our 1960s full frame SLR and mount it on our half frame camera (digital whatever, or half frame 1960s SLR, Konica Auto Reflex maybe?), and take two long steps backwards. We know we need to double the subject distance - because of the laws of similar triangles - to obtain the same crop on a half frame media.

 

Now,

For the subject's eyes, at s=4 meters, the image is formed at distance

s'=(4000 x 135)/(4000-135), or 139.7mm behind the lens.

 

For the subject's nose (which has NOT doubled in length), at s=3.9 meters, the image is formed at distance.

s'=(3900 x 135)/(3900-135), or 139.8mm behind the lens.

 

The image of the nose is MUCH closer to the image of the eye (only 0.1mm out of focus).

 

An error which is only 1/6th of the full frame crop.

 

This assumes of course that the aperature selection was the same in both instances.

 

At least in this choice of lens and distance, the DOF has expanded by a factor much, much greater than the factor of 2 change in image size.

 

Conclusion: The key is that the subjects nose does not lengthen by a factor of 2 when we step back. The geometry is not similar. Deeper DOF by using the same lens and stepping away from the subject to maintain the same crop.

Credit to Francis A. Jenkins and Harvey E. White.

After firing off my previous post, I re-read your DOF comment, and now understand the question. Please forgive me. If you back away from the subject to obtain the same crop of the image on the media size... The geometry isn't similar (and neither is the perspective for that matter) anymore. I'm pretty sure they're independant of one another - at least it's not linear... Well I don't know! I'll have to consult my Jenkins and White.

The DOF of the real image generated by the lens is the same when it falls upon an under-sized chip, as it is when projected upon a sheet of film - as long as the same aperature is selected. Nice review of the camera. Well-written. I'd like to see more posts like this.

I find that the resolving power of the film is most limiting, and that just about any lens - if properly focused - will generate an image in the film plane beyond the capabilities of the film to record.

 

In light of this discovery, I've foregone using film, and now just view aerial images of my subjects, using a small microscope focused on the film plane.

Having read this thread, I am sold. I'm going to put a 35mm lens flange on my 110 camera.

Shoot your sixties/seventies/eighties typical 35mm SLR with BOTH EYES OPEN, and you'll immediately know why a focal length of approximately 50mm is going to be considered "normal" for most SLR viewfinders.

 

SLR designers have established (or re-enforced) the image diagonal as the "normal" focal length, by standardizing the viewfinder to match normal vision with a 50mm lens.

 

This discussion thread (and many like it) is just an indication of how many people shoot with one eye closed.

Note that the focusing ring gear rack is cut to limit travel, such that travel stops at infinity when the idler is installed.

 

The C3 lens can be removed as follows. Focus at minimum distance first, to move the lens away from the camera, and provide clearance for the knurled knob in the next step.

 

Remove the knurled knob over the idler gear.

 

Remove the idler gear.

 

Rotate CW to the infinity hard stop (lens closest to body). Note exactly where some feature on the face of the lens (f-stop hash mark?) is relative to the camera body.

 

Turn the focusing barrel CCW until you hit the hard stop at minimum focus, and then keep turning it CCW.

 

NORMALLY, the additional torque will unseat the lens base threads from the camera body, and the assembly will come off. If the lens base threads are stuck in the camera body however, then the additional torque will pop the focusing ring pin out of the focusing ring slot.

 

If this happens, carefully slowly continue unthreading the lens assembly, and note the relative position of your chosen landmark when you feel the threads end.

 

Remove the now exposed snap ring, slip off the focusing ring, and use a strap wrench to unstick the stubborn brass lens base from the camera body.

 

Reassembly is complicated by the fact that the focusing threads are cut with 6 threads. You've got a 1 in 6 chance of randomly matching the threads (and focusing relationship). Obtaining the previous relationship is an iterative process unless you noted where the face of the lens was oriented with respect to the camera body at the hard stops BEFORE you over-torqued CCW and popped the pin out of the slot on the focusing ring.

 

With 6 possible threads, it is always a possibility that somebody has mis-assembled it by a thread in the past.

 

Always use a piece of ground glass held to the film plane, and a loupe to check the focusing - against the distance indicated on the range finder, with the shutter held open on B. This should be done with all cameras.

 

When the idler is properly re-engaged, the travel should stop exactly at the infinity point. Adjust the idler engagement as necessary.