john_ratliff1

That lens, at f-1.4, gives us all a lot of opportunities. I like the effect, and with a reasonably fast film, we can take photos where people don't think that they can be taken. For instance, you can take an indoors photo, bounce the flash, and still use a reasonable f-2.8 or so. The enclosed photo was taken with a Canon FT-QL, using a FL55mm, f-1.2 lens.

John

I have gotten some very good night shots with the concave element SSC 35mm, f-2.0 lens too.

John

I used my F-1N just yesterday, and enjoyed it too. I did just buy a Canon Rebel XTi too, but

have a lot invested in the Canon FD line, and will continue to use it, so don't look for mine on

e-bay anytime soon.

John

That should have been "18 years of age" in the quote above. 'Sorry about that.

John

According to a quick Google search, the radioactive elements in cigarette smoke are:

--Polonium-210 (Po-210)

--Lead-210 (Pb-210)

--Radium-226 (Rd-226)

Radium-226 decays into radon, and Po-210 and Pb-210 are "long-lived decay products of

radon. Sticky hairlike structures on both sides of tobacco leaves collect these from the

atmosphere. Tabacco roots also absorb some radioactivity from the soil." K.S.

Parthasarathy, Secretary, AERB, source:

http://www.hindu.com/thehindu/seta/2003/06/05/stories/2003060500020200.htm

According to this internet source, Carol W. LaGrasse, P.E., member Adirondack Branch

Advisory Council of the American Lung Association of N.Y. State, 1986, "For a person

smoking 1 1/2 packs of cigarettes a day, the annual radiation dose to the surface of

bronchial cells at bifurcations is the equivalent dose to the skin from taking 300 chest X-

rays per year." Here's that source:

http://prfamerica.org/RadioactivityInCigaretteSmoke.html

I'm concerned here as my Mother died of lung cancer and emphasema from cigarette

smoking. I am currently taking a course in Epidemiology from Tulane University Center for

Applied Environmental Public Health, and read the first chapter of my text today. In it, Dr.

Leon Gordis ("Epidemiology, Third Edition) states:

"Consider cigarette smoking and lung cancer. We do not know what specific component in

cigarettes causes cancer, but we do know that 75% to 80% of cases of lung cancer are

caused by smoking...Since 1987, more women have died each year from lung cancer than

from breast cancer. Thus, we are faced with the tragic picture of a preventable form of

cancer, lung cancer, which results from a personal habit, smoking, as the current leading

cause of death in American women.

"Furthermore, in 1993, environmental tomacco smoke (secondhand smoke from other

people's smoking) was classified as a known human carcinogen by the Environmental

Protection Agency, which attributed about 3,000 lung cancer deaths in nonsmoking

individuals each year to environmental tobacco smoke.

"Although rates of smoking in those older than 189 years of age appear to have decreased

in recent years in the united States, a troublesome observation is that, from 1991 to 1997,

the prevalence of smoking in high school students increased 32%. Thus, the scourge of

smoking remains one of the major unmet prevention challenges for practitioners inbo th

public health and clinical medicine." (page 13)

The difference between the lens exposure and cigarette smoke is three-fold:

--Cigarette smoke is an internal hazard, whereas the lens has radiation outside the body.

--Cigarette smoke's radiation is in direct contact with interior lung tissues and cells,

whereas the lens is outside the body, and the distance is much greater.

--Cigarette smoke's radiation is mostly alpha radiation, which is not really dangerous until

it gets inside the body, and then it is deadly. Alpha particles are huge compared to other

particles, and whereas it does not penetrate deeply, what it hit it really wacks hard. In

converting rads (radiation absorbed dose) to rems (radiation equivalent in Man), a quality

factor is assigned to various types of radiation. For X-rays, beta radiation, and gamma

radiation, that factor is "1". For alpha radiation, depending upon the energy level, that Q-

Factor is 1-20. If the alpha-emitter is 20, and it is next to the tissue, the tissue is

absorbing 20 times the damage from that radiation than if than radiation was an X-ray.

So if your choice is between using the Canon FD F2.0 lens with the thorium-floride

element, and qutting smoking, by all means enjoy the lens and quit smoking.

John

Jeff,

I took the lens on my Canon F-1N, with a power winder and an AE Finder FN mounted on it

the body. I met with a representative of ThermoFisher, who makes the Mini900 GM

counter that I use. I wanted to show him the ionizing radiation source that I was using in

the training. In the process, I was able to get measurements of the radiation at the eye

cup of the AE Finder FN with the 35mm F-2.0 lens. Here are the measurements from

today:

--At 1/4 inch off the lens focus ring, 1-2 uSv/hr, settling to about 1.5 uSv/hr over time

(as reported above).

--At the eye cup, where the eye would be, 1 uSv/hr (it settled there, and varief from about

0.6 to somewhat over 1.0 uSv/hr).

Again, these are not high, but are above where my company measures for a radiation leak

on our machines (0.6 uSv/hr).

For the sake of clarity, I will repost the typical radiation from above. I am doing that

because above it did not come out in tabular format, and is therefore hard to see. Here is

what it should have looked like:

Natural background and manmade radiation (annual average dose equivalent, including

radon): 360 mrem

Diagnostic chest x-ray: 10 mrem

Flight from LA to Paris: 4.8 mrem

Barium enema: 800 mrem

Smoking 1.5 packs per day - 1 year dose: 16,000 mrem

Heart catheterization: 45,000 mrad

Mild Acute Radiation Sickness*: 200,000 mrad

LD50 for Irradiation*: 450,000 mrad

Note, these have two units, mrad and mrem. The "m" stands for "milli," and is 1/1000.

"Rad" is "radiation absorbed dose," and "rem" is "radiation equivalent in man," which uses a

multiplier for the type of radiation, as different types have different effects on biological

systems (alpha verses beta verses gamma verses x-rays, for instance). Also note the dose

a smoker is receiving.

I also gave annual regulatory limits (USA--other countries may be lower in some cases,

higher or non-existant in others):

Members of the public: 100 mrem

Occupational limits:

Total effective dose equivalent: 5 rem

Lens of the eye: 15 rem

Single organ dose equivalent: 50 rem

Skin dose equivalent: 50 rem

Extremity dose equivalent: 50 rem

Hopefully, this will come out easier to read.

John

Jeff, I'm going to take my F-1N to work tomorrow, when we have an instrument dealer coming over, and take some more readings to see what I get.

Frederick wants some comparisons, and Daniel gave a few. But Daniel compared two separate risks (driving with ionizing radiation) that do not include the radiation. This is still somewhat valid for looking at overall death rates, etc., but not for tissue risks. I did take a radiological health course from Tulane University's Center for Applied Environmental Public Health (CAEP) last winter (I'm studying for a Master's Degree in Public Health--Industrial Hygiene) and received these comparisons in a slide:

Natural background and manmade radiation

(annual average dose equivalent, including radon): 360 mrem Diagnostic chest x-ray: 10 mrem

Flight from LA to Paris: 4.8 mrem

Barium enema: 800 mrem

Smoking 1.5 packs per day - 1 year dose: 16,000 mrem

Heart catheterization: 45,000 mrad

Mild Acute Radiation Sickness*: 200,000 mrad

LD50 for Irradiation*: 450,000 mrad

(mrem = millirem = 1/1000 rem; 0.6 uSv/hr = 0.06 mrem/hr; 1 Sv = 100 rem)

Annual Regulatory Limits:

Members of the public: 100 mrem

Occupational limits:

Total effective dose equivalent: 5 rem

Lens of the eye: 15 rem

Single organ dose equivalent: 50 rem

Skin dose equivalent: 50 rem

Extremity dose equivalent: 50 rem

5 rem = 0.05 Sv = 50 mSv

So lets say the lens of the eye receives 1.5 uSv/hr from the Canon lens. Since 1.5 uSv/hr equals 0.15 mrem/hr, that would be 0.15 mrem/hour, and the dose limit is 15 rem per year. To get a year's dose, you would need:

0.15 mrem/hr x 1000 mrem/rem x 15 rem/dose limit = 2250 hours on the lens to get the year's dose limit of ionizing radiation from this lens.

This sounds like a lot, but remember that ionizing radiation is not the only cause of cataracts. So is non-ionizing radiation, like sunlight. There are be cumulative effects, as airline pilots have a higher rate of cataracts than do the rest of the population, and that is thought to be because of ionizing radiation from space, which doesn't have the atmosphere to blunt it.

This gets us back to the ALARA concepts above. ALARA is defined as:

"ALARA (?As Low As Reasonably Achievable?) means making every reasonable effort to maintain exposures to ionizing radiation as far below the regulatory dose limits as practical, taking into account economic, societal, and other relevant considerations." (Dr. Ronald Goans, Tulane University Center for Applied Environmental Public Health)

Here is how to minimize exposures to external ionizing radiation:

--Minimize the time spent near the radiation source

--Maximize the distance away from the source

--Make use of available shielding

--Minimize the quantity of radioactive materials handled

As stated in my first post, this is a minimal hazard for ionizing radiation, which is why I felt comfortable carrying and using the Canon FD 35mm, F-2.0 lens above. But that also means that I will not be using it regularly, or even occasionally. I'll use it only when I feel an acute need, and realize that I am absorbing some radiation dose when I do.

John

Another photo with this FD 35mm, F-2.0 Lens, taken on one of my walks. It is of a fountain

on the Great American Expressway.<div></div>

The above photo was made with Fuji ISO 50 Velvia slide film. Here is another, of a building

which is reflecting an image.<div></div>

Have you wondered about the potential radioactive hazard for the Canon 35mm F-2.0 SSC lens with the

radioactive thorium-fluorite element? Well, let me answer this after a few lines of introduction to a

problem I had recently.

I am an industrial hygienist, who was tasked with the job of providing some training to our customer

engineers for a high tech firm where we had a machine which emmitted X-rays. We needed to train

them in the use of our new ionizing radiation detectors, one a scintillator and one a Gieger counter (see

http://en.wikipedia.org/wiki/X-ray for details). But I did not have a source of ionizing radiation to

use. I tried to use a lantern mantle, but they have gone away from the radioactive types. I tried other

sources, like table salt (which has low levels of radioactive potassium iodide in it), but that did not work

either. Finally, I found my source.

The source was the Canon 35mm F-2.0 lens mentioned above. This lens contains a radioactive thorium

floride lens element in it. Here is what Wikipedia and others say about the lens.

"Added to glass, it helps create glasses of a high refractive index and with low dispersion.

Consequently, they find application in high-quality lenses for cameras and scientific instruments..."

http://en.wikipedia.org/wiki/Thorium

"Note: incorporates radioactive, thorium floride ("rare earth") glass which imparts a warm green tinge to

the pictures. Best use as an exceptional quality lens for black and white photography, since it doesn't

match the color of other Canon FD lenses and will color cast color slides. Very high contrast at all but f/

5.6 and f/8 where it is extremely high. Optimum aperture f/5.6." See the below link for the lens (scroll

down), as it has the ratings at various stops as well as the other information quoted above.

http://members.aol.com/canonfdlenstests/default.htm

I have now used the lens in several training sessions. We need to train our engineers to be able to

detect faint X-ray leaks on our machines. We use the level of 0.6 microSieverts an hour (0.6 uSv/hr) as

our cutoff, which is very low. We do this, even though the average person traveling on a passenger jet

will receive more than this amount, because of the principle known as ALARA. ALARA means that there

is no amount of radiation that is "safe," and that even though the body has mechanisms for coping with

radiation damage, we don't ever know that that damage will lead to cell mutation from DNA damage.

ALARA means "as low as reasonably achievable."

See; http://en.wikipedia.org/wiki/Sievert

for more information about measuring radiation in microSieverts.

We first survey with a scintillation detector, as it will detect the low levels in a rate-count mode (counts

of ionizations per second) that is very low. It alarms at 75 counts per second. I had several items

scattered on a desk, and asked a engineer to survey those items, as one was a radiation source. The

alarm sounded at 87 decibels when the engineer moved the detector over the lens, about half an inch

from the lens, and she jumped back surprised. The counts per second reading went to about 150 cps.

We then took the Gieger counter and got an accurate reading of the actual radiation. It read between 1

and 2 microSieverts per hour (1-2 uSv/hr), settling at 1.5 uSv/hr for a time. At the eye cup, the reading

was about 1 uSv/hr.

What does this mean to us as photographers? Well, I was carrying that lens around all week, and took a

lot of photos with it. Because I was using it as a prop, I wanted to have it there all week. I got a camera

pass, and it turns out I had the only camera pass at the safety workshop. But I took care not keep the

lens to my eye for any period longer than necessary to focus and take the photo. I also walked a lot (I

decided to walk rather than use a rental car for the week), and had the camera strapped over my

shoulder. I normally rest my lower arm over the camera and lens, but decided not to with this one. The

Wikipedia link above states that this is alpha radiation, but it is not stopped by paper (which I confirmed

with the Gieger counter). I therefore think that at least some of the radiation is beta radiation, which

can go out a bit further. The radiation drops off very quickly, and is not readable about four inches

away from the lens. But if you think about it, every second that my eye is at the camera to take the

photo, I'm receiving about 150 ionizations. These add up in a hurry. I have therefore discontinued

using this lens for all but the radiation survey courses.

Why? ALARA--I want my exposures to radiation kept to a minimum, and if I have no need for that

exact lens, I will have no further exposures. In the scheme of things, this exposure is pretty minor, but

if it is preventable, then I will prevent it. One of the effects of ionizing radiation is an increase in

catarachs, and this is something I would like to avoid too. It must be emphasized that this is not

whole-body dosing, but very limited to a small part of an arm, and the face. But all ionizing radiation

interactions will have an effect, and I wish to minimize them on myself. What does this mean to

photographers? I don't know, as everyone will have to make up their own minds. But at least you have

some information to go on. The lens is a very good one, and I've enclosed some photos to show its

capabilities.

John

PS--I posted an earlier story associated with this trip, which was removed. If I offended anyone with

that story, my apologies. I was simply trying to describe the evening as it happened.<div></div>

Santa Clara, California, Canon T90, 35mm f-2.0 FD lens, shot at f-8, shutter speed

unrecorded.<div></div>

I'm looking at my 55mm F-1.2 Canon FL lens right now, on my desk. Seeing you photos

shows me that it is good for something other than as a loop to look at slides.

Thanks,

John

Wow, that is really clear and sharp. I like it.

John

I forgot to tell you about the other part of it, the use of the 299T. On the back, there is a

mode selector that says "Program" and "F. No. Set." Select the "F. No. Set" and set the F

stop that you want the flash to think you are using. If you are using F-16, then select

F-5.6 for the flash to get a 2 stop under-exposure for the shadows. The flash will think

that the camera is opened to F-5.6, when in fact the sunlight exposure is F-16. The flash

will then shut down with a 2 stop underexposure.

There is a lot more to flash fill, which I don't have time to discuss. You can learn it by

picking up a copy of an older book, "How to select & use Canon SLR Cameras" by Carl

Shipman (third edition to include the T-70 and 299T strobe).

Enjoy,

John

I had a T-70 for quite a while, and got very good photos with it. But you need to

remember that the T-70 automatically sets the shutter speed at 1/90th of a second, and

there is only one way to keep the camera from doing that--tape the two small contacts on

the top of the camera. Then select a shutter speed that you want in the TV mode, and use

the camera that way. This disables the auto functions of the camera, and the strobe which

usually sets the F-stop won't do it. So the camera is taking an ambient photo and the

strobe is then deciding what to do thinking that the camera is at a certain F-stop. What

you want the strobe to do is to provide "fill flash." To do this, it must expose the subject

about 1/2 F stop higher (lighter exposure) than the camera. What this does is give you the

ability to do photos that a T-90 could do, with lower light, and get the background.

Now, the ocean beach is a different story. Here, you probably want to act like you have a

manual camera, and use it in manual mode. Take the meter reading off your subject's

face, or use a neutral gray card, and get the exposure correct. Then, you can do a few

different things with the strobe. The 299T is a wonderful strobe for the T-70, actually

made for it and the F-1N, and it has a 1/4 flash manual function. This would probably

give you a good flash fill.

Anyway, try these, and see how they work before you go to the beach, or on the first day

take a negative film and get it developed immediately to see your results (one-hour

photo). If you have time, take some slide film and record every setting using these

techniques before you go to the beach. Then you will know better how the camera

responds.

John

Here's what my Canon T90 brochure (Pub. CE-249A, 1985) says

about the ML-2:

MACRO RING LITE ML-2

FULLY AUTOMATIC TTL

CLOSE-UP PHOTOGRAPHY

The Macro Ring Lite ML-2 is a two-flash-tube ring-type TTL

electronic flash designed for exceptionally simple close-up

photography. Makor features include:

--Two flash tubes can operate separately or together

--Convenient focusing lamp

--Versatile modeling lite

----------------

They show a photo of the ML-2 on a T-90, and a photo of a red

ladybug with black spots on a blade of grass.

John

It's funny that this comes up today, as I was using my F-1N with

the Speedfinder to photograph an intersection where I was

nearly killed on a bicycle. I have been using the Speedfinder on

my F-1N for many years, and bought the camera because it had

that capability. Why? Well, I'm an underwater photographer, and

I needed a camera I could use in an underwater housing and

see the whole image. The F-1N with Speedfinder is great for

this application. I also wear glasses, and it is a great help. You

can also reverse the finder, and sit the camera on the ground to

get a photo without laying down yourself. I've found it very useful.

John

Alan and John,

I wish you guys would not make these kinds of entries into this

forum. It is not appropriate on a forum that is going to be looked

at throughout the world.

John

I have had a lot of different FD camera bodies, but my favorites

for feel are the F-1N with a PowerwinderFN and the T-90. Both

feel excellent in my hands. I think Canon spent a lot of time on

the ergonomics of these bodies, and it paid off.

John

<img src="http://d6d2h4gfvy8t8.cloudfront.net/3113818-md.jpg">

Ray,

Thank you for showing me how to do this. I'm at my allotment for

images right now, so maybe I should sign up for a portfolio.

This image is of a ling cod, taken on the same dive, and again at

a slow shutter speed (1/8th second). Because it is slower, and

because I startled it just as the image was being made, there is

a great blur when the fish quickly swam away. I like this kind of

image, but you never know what it will look like until the slides

come back. All these were Fuji Valvia, I believe, at ISO 100

speed. I like Fuji better for my underwater photography because

of the vividness of the colors; underwater photos loose contrast

quickly, and the film does make a difference. Becaus this photo

was taken close (about 4 feet away from the fish), the flash

image fully defines the fish. The explosiveness of it's retreat

then shows only as the blur, which shows the swimming motion.

John

Anyone have some input into what I'm doing wrong here? In

other words, HELP!

;-)

John

I'll try once again:

<img

src="http://www.photo.net/photo/3111874.jpg

">

Use the text above for the description, but I will add that the lens

was the FD 24mm f-2.8 lens.

John

<img

src="http://www.photo.net/photo/3111874">

This is a photo of divers approaching a large, resident ling cod at

Edmonds Underwater Park in Edmonds, Washington. This park

has seen no spearguns for over 25 years. Camera, a Canon

F-1N with Speedfinder, 24mm lens in an Ikelite housing, behind

a dome port. Strobe fill was with a small Ikelite MS strobe. Lens

was at f-5.6, shutter speed at 1/8th second.

John