denton_hoyer

Hi Folks,

I currently use 5D and am wondering if getting an XTi as backup would really

provide an increased magnification with my current lenses. Is the arguement

that having a 1.6 crop camera the equivalent of doubling my lens inventory

valid? I might be able to simply crop the 5D image until the image size was

identical to the 1.6 crop body but how would the quality compare? Anyone done

the test?

Denton Hoyer

Anyone use a polarizer for portraiture? I'm thinking this may be a good way to

attenuate glossy skin reflections. One might be able to set the polarizer by

reflecting off a small piece of glass held near the subject.

Denton

Thanks folks,

I'll restart this topic on the General Forum section.

Denton

I'm somewhat puzzled where this post would be most appropriate, so if

I've misjudged forgive me. There seem to be no forums dedicated

exclusively to the interpretation or enjoyment of B&W Art to the

exclusion of all media.

Anyway, I think lovers of B&W would enjoy, as I have, "Good Night and

Good Luck" by George Clooney and Grant Heslov. The film contains

many scenes which are practically stills and wonderful lighting, all

done in B&W.

Enjoy,

Denton

One person's experience doesn't constitute a statistically reliabilit record, so my flawless Bessa R2a doesn't mean much, nor would anyone else's experience, good or bad.

I can say this camera is not flimsy, judge by any standard other than Leica. You will find it's metal case much more solid than a Rebel, for example. I will give you pictures equal to your skill. I can vouch for the portability of a rangefinder,if it is film you want to use. My lenses are the limited edition screw mount 50f2 Summicron and the CV 35f2.5 lens. I love them both. The CV lens is my favorite, even over the Summicron due to my preference for the wider angle, especially necessary indoors and give very nicely composed shots for close-ups when you can't back up for a 50mm. The 8x10's are sharp edge to edge (Ilford Delta 400, xtol 1:1 shot at ISO400 or 320). The shutter needs a battery to operate, so that may affect your choice. Keep in mind that rangefinder lenses are not as close-focusing as slr's and so I find the images need to be larger than those composed for the close focusing slr.

Best purchase I made this year.

Denton

The 50mm f1.4 prime is better than the 17-40 zoom set at 40mm in terms of chromatic abberation and resolution at the edges. It seems equal in resolution at the center.

I would expect many primes to equal or exceed L zooms at the equivalent focal length and f-stop, especially with respect to wide angles for which zooms suck.

Denton

Primes, zooms and rangefinder glass.

Erie, I just realized you don't have the shutter speed either. I assume you've figured out that the shutter goes from 1/500 to one second. The bolt hole I measured from is at the 1/500 side. The click stops on the shutter should allow you to set them, of course.

What a pain for you.

Denton

Hi Erie,

This is easy if you have the shutter speed scale. The f-stop markings are exactly in between the shutter speeds. The positions for 150mm are 250/125=f5.6, 125/60=f8, 60/30=f11, 30/15=f16, 15/8=f22, 8/4=f32, 4/2=f45, 2/1=f64. That should be pretty close. If you still can see the two screw holes for the scale attachement bolts, then you can use the following measurement from the center of the bolt which are f5.6=13mm, f8=17mm, f16=25mm, f22=29mm, f32=34mm, f45=37mm, f64=42mm. This should be more accurate than a photograph with spherical distortion!

Good luck,

Denton

Erie,

The two focal lengths on the shutter are 150 and 450mm. The 450mm set of f-stops are simply three higher than those at 150. For example, the following pairs are found for 150/450: 5.6/16, 8/22, 11/32, 16/45,and finally 22/64. So if you want equivalent f45 for 450mm, set the indicator to f16 for 150mm.

I haven't checked the focal length of the converted lens since my camera is a Toyo 45CF and although it can take 300mm, it's not going to bellows out to 450mm. I can pull the lens off and extend it manually, but this is technically more demanding!

Good luck,

Denton

Hi Folks,

Would someone be able to educate me regarding what I believe to be an

original Rodenstock Sironar 150mm f5.6? The serial number indicates a

1973 manufacture (#8723680) and the shutter is #0 Copal with what

looks like to aperture ranges for 150&450mm. I assume this is a

single coated design (plasmat?) The filter size is 67mm. How would

this be converted to the longer 450mm and is this an improvement over

my current 150mm f6.3 Geronar. Despite extensive Googling, I've come

up with blanks.

Thanks a bunch for what is likely trivial information,

Denton

Read what Iris Davis has to say about TMAX:

http://www.chrisjohnsonphotographer.com/funfilm.shtml

Bought the Bessa R2a, Color Skopar 35f2.5 and yes, it's easier to focus than either my spotmatic with 35mm takumar, rebelxt and slightly better than my F2 (with 50mm, don't have 35mm).

Nice small package, fits in a coat pocket. This is going to be a fun camera.

Denton

OK,

Foaters are transparent globs that fill the vitreous humor of the eye. What happens is they move slowly over a period of weeks and often cover that portion of your retina that has your point of focus. To some extent, I think I could focus with peripheral vision and here is where I think a rangefinder focuser might help. Composition is no problem as it doesn't depend on perfect focus. Furthermore, bright viewfinders don't help floaters.

Additionally I still have problems gettting consistent focus even with a 50mm f1.4 lens, although it's better than a slow lens. Focusing a telephoto is much easier.

Two problems to deal with

I may just have to order a cheap (Bessa) rangefinder and check it out. I just wish a digital full frame rangefinder was available, but then I wouldn't want to pay for it.

But hey, I'm only 48.

Denton

Dirk,

If there is a current patent on this device in the United States you may not sell it here. Go to this US patent office link and read:

http://www.uspto.gov/web/offices/pac/doc/general/index.html#patent

Sorry,

Denton

Thanks for all the replies. Yes, the old F2's and OM-1 cameras had large bright finders. I'm wondering whether I need a completely different type of focuser though. I suppose the extreme might be a medium format rangefinder like the Fuji's. Not living on the east or west coast, I often have a good drive to any well-stocked camera store.

Denton

To clarify, Leica needs a valid UNITED STATES patent in order to protect their product in the US. I suspect they do this as a matter of course in their major markets. Your device would have to be novel and non-obvious to get a patent if that is your objective and this is harder to achieve than it might first seem.

Denton

You will need to see if a patent has been granted covering this device in the United States. A patent agent or attorney could do the search for you, or perhaps a librarian at a large public or university library could help. I do these searches myself, but have access to the databases. You will have to read the patent and usually it's fairly clear whether your idea is radically different. It is up to Leica to sue you for patent infringement, the US government just grants them they don't enforce them. There are lots of ways around a patent, but you need to read up on what constitutes a valid patent and educate yourself. I am not an attorney, but deal with pharmaceutical patents on a regular basis.

Denton

Hi Folks,

I'm attempting to deal with my failing eyesight and it's effect on

manual focusing. I do have both the Canon Rebel XT and the

equivalent film T2 camera and find this is a good solution for auto

focus. However,the small viewfinder of these cameras doesn't allow

for confident manual focus, especially at 50mm and less. I'm dealing

with both many floaters and poor accommodation. So is a rangefinder

the best solution for manual focus at 50mm and less? Will the

rangefinder baselength be important to consider at these focal

lengths or is it not important unless i go telephoto? Another option

would be to go full frame DSlR, but I still have some trouble with my

F2 and a 50mm lens so the SLR route probably isn't going to be any

improvement.

Thanks!

Denton

This Nikkor is probably one of the best lenses for "wide field" astrophotography. See this shot:

http://www.photo.net/photo/3916020

What is remarkable is that this lens is sharp on a star field (think pinpoint lights) clear to the edge at wide open. I've shot many lenses wide open and they almost all show coma or severe chroma at the field edge. So, this lens performs well at infinity, not just portrait distance.

Perhaps an equally good lens is the Nikkor 180f2.8, but it's just a bit too long for unguided astrophotograhy.

Just my two cents. I'm shooting both these lenses on my RebelXT with the NEOS adapter. Of course, I shoot them using my F2 as well!

Denton

The toyo 45CF will take a 300mm lens at full belows extension and you can get close enough for portraiture if you insist on using that lens. I find the 150 mm lens is fine for portraiture. This camera is extremely light and IMHO, well built. It will also fold with the 150mm lens inside.

Denton

Sergio,

You could light ten people with one B800 in an umbrella as key somewhat to the side and use a speedlight for fill near the camera. The problem with one light is moving it far enough back so it doesn't fall off more than 1/2 stop from one edge of the group to the other. Using two lights would do it easily, but unless you experiment you won't know what you like. You might not like the flat lighting as much as a key/fill studio approach.

Good luck, Denton

I think you should leave the lights up to her (but I like alien bees). If she shoots protraits with film, she is really going to need a good flash meter. Look at a top of the line sekonic. She will need this since she can't get the immediate feedback of digital and will have to nail the shots most of the time. If a combination spot, incident and flash meter sekonic is out of your budget, go with just a good incident/flash meter, like the Minolta or Gossen.

Denton

Denton

Steve wrote, "In a TTL system, typically the regular light meter attempts to meter the scene to find the ambient light, and the aperture/shutter are set appropriately. Then, when the button is pressed, the TTL pre-flash is fired, and the TTL sensor reads the amount of light needed to reach that of the ambient light level, and adjusts the output of the flash to match".

I don't think that simple description from the flash manufacturer's is very informative. It tells us how they think we normally should use the flash and really says little about how it is accompllished and that was my question. Actually, I didn't ask about TTL but Auto, which is metered differently.

So again, does the sensor measure total radiation or change in radiation?

Hi Folks,

A question for the electrical engineers or otherwise illuminated. An

auto flash feedback sensor in an outdoor fill flash situation is able

to provide the right illumination, despite having an equivalent

ambient level of illumination. My question is how is this feedback

accomplished, i.e, is the sensor able to distinguish a flash

discharge energy vs. ambient radiation? My guess would be the

circuitry is designed to respond to changes in illumination, not

simply the absolute level of illumination.

If there are no informed opinions, then I'll just have to do some

trials with my vivitar and sekonic flash meter to find out, and since

we may be snowed in here in Michigan it might be just the ticket.

Takers?

Denton

Thierry,

My exposure meter (Sekonic 508) can be set in flash metering mode using different shutter settings and I've always assumbed this would make a difference in cutting out the ambient contribution using high shutter speeds. I could double check this as I don't recall doing the experiment. In this case it would, of course, be important to set the shutter speed on your meter.

A related question to which I don't have an answer involves auto flash units which have a light meter sensor. I don't understand how these sensors can properly meter a fill flash outdoors. In this case you normally set the auto flash at one stop less than the ambient background. The flash is therefore being bombarded with a one stop overexposure of ambient, yet it still senses the flash and shuts the voltage off after the correct flash exposure has accumulated. The only thing I can figure out is that the flash circuitry considers only an increase in exposure to be significant and somehow derives a baseline from ambient. Does anyone know how the auto feedback is determined?

Hope you don't mind me hijacking your question.

Denton