wideopeniris

Don't be too hasty! Yes these cameras are notorious for spacing issues. No it isnt always that there is a fault in the camera.

Loading the P6 must be done with care. See:

How to load the Pentacon Six / Exakta 66

Once I learned how to do this correctly my P6 spaces pretty well.

Why is it so fussy? Well there being no sprocket holes on 120 is an issue for the winding mech. In the p6 there is a friction clutch connected to the small roller next to the take up spool. This detects how much film has been wound and stops the wind lever from continuing to transport the film. It relies on the sharp serrations on the wheel engaging with the film at all time. If the film is loose then it allows the full travel of the lever to wind the film without the clutch disengaging the mech. - that results in ever wider spacing as the spool fills with film. So its important that the film is tight over the pinion on the roller - I usually like to leave a definite mark on the film.

So it may be worth another roll of film following the instructions carefully. Its still possible that the friction clutch has failed - they are often a victim of people using lighter fluid flush to free up the shutter and can wear out over time. The wind mech can also be damaged by to rapid return of the lever so always return the lever gently.

Good luck! When working they are great cameras for 6x6 on a budget and the lenses are great.

Kevin.

<p>The picture you are referring to was shot in a room with curtains in the background that have a large amount of small details in a regular pattern. Even when extensively blurred, there is still that distracting harsh looking background. The shot was an experiment, and I would normall have opened the curtains to remove the distractions. If you look at the beard, you can see that it is very sharp and there is no movement in the shot.<br>

If you look at the other shot on photo.net of the lady, you can see that the plane of focus is actually in front of her face, and yet the blurr is not unpleasant - an interesting effect (her right wrist is sharp). This was caused by a (very) small error in the GG position on my camera. I had to shim it by 0.4mm to correct the plane of focus between film and GG. This is the other problem of large aperature lenses.<br>

You are correct I think about the magnification of the blurred objects. So DOF is constant, but the blurring of background objects a long way behind the subject is greater. So I was not entirely correct. However the effect is not as dramatic as increasing format size.<br>

The reason for my question was to determine whether it was worth using a longer lens of similar aperature (with the attendant weight and inconvenience not to mention cost) for use in portraiture. I normally use my fast lenses stopped down to f3.5 or f4, so its like using an f1.0 lens on 35mm. As you say this doesnt allow low light shooting, but these are posed daylight shots. I get out my 35mm camera for candids.</p>

<p>Kevin.</p>

<p>I actually use a scale factor of 4:1 for 35mm vs 5x4. You almost always crop the edges off a 24x36mm frame when printing in 35mm, and so the short edge defines the ratio - i.e 96mm/24mm - exactly 4:1.<br>

There are three moderately common lenses on 5x4 - The Schneider 150mm f2.8 Xenotar, The Kodak Aero-Ektar 178mm F2.5 (aerial camera lens for 5x5inch) and the Dallmeyer Pentac 8inch (210mm) f2.9.<br>

I cant afford the Schneider. I have an Aero and a pentac, and the pentac is my favourite. The aero is the sharpest wide open and is slightly faster, buts its huge and heavy. Also its suffers from mechanical vignetting at the edge of the field giving 'cats-eyes' in the blur of point lights in the background and giving slightly harsh bokeh. The Pentac is has less vignetting and by f4, where I use both lenses most often, its blur disk is smooth and round right to the edges. The sharpness is perfectly adequate for portraits and its more contrasty than the Aero (but not much - I'm lucky as my pentac is single coated).<br>

In addition there are plenty of tessars at F3.5 and almost any focal length. Also there are a few f2.7 and 2.8 tessars. But the 3.5s are much sharper wide open. The field curvature on the tessars makes the edge of coverage soft. Then finally there are some ektars that are double gausses that have f4.5 down to about 120mm for something wider.There are many 4.5 lenses out there like (hi cost) heliars etc. Mostly speed lenses for press use in more or less 'standard' focal lengths.<br>

The 420 3.5 projection lens is for an epidiascope - the sort of thing used for projecting book pages in a lecture hall. I expect it to be soft at the edges, but a cooke is pretty good in the central 2 thirds.Having projected an image onto a GG I am confident it will at least be interesting. It renders an almost painting like effect with still lifes. I'm inspired now to get it mounted...<br>

Kevin.</p>

<p>Andrew: the 420 3.5 is a projection lens. It is a triplet in the style of a cooke lens. It covers 10x8 (!) with ease, being about 42 degrees at 420 giving an image circle of 300mm diameter. But over this angle its a bit soft at the edges as you might expect. But over 4x5 its plenty sharp enough. Also its coated which means its actually quite contrasty (I have an agfa apotar for 6x6 which is a triplet and at f8 its sharp and by far the most contrasty lenses I own - so dont sniff at triplets..)<br>

Only problem is that its 130mm diameter and the back focal length is large (250mm). It also has no diaphragm. So its going to be a bit of a project to make , in effect, a custom camera with focal plane shutter and modifying the lens to add waterhouse stops or something. At the moment its on the back burner...<br>

The 915 f6 is just crazy. Its a white elephant, though an interesting one. An APO-Tessar type design with evil blade shutter and weighs some 7kg originaly for high altitude aerial photography on 18x18in film.</p>

<p>I guess its a matter of subject. I'm referring to portraits, and mine are often head and torso or head and shoulders. My subject distance is usually about 3m. On small cameras the magnification is definately small. On LF its getting a bit bigger, but still of the order of 1:10. In your 14mm example, magnifaction is only 1:2 and I see your argument completely (havent had a chance yet to look at your spreasdsheet).<br>

The 200 F2 - you paid for aperature mostly at a focal length that gave you the right magnification. No need to feel silly! (I might manage envy except that I have a 420 f3.5 to one day mount on my 5x4 that cost nearly nothing...dont mention the 915 f6...)<br>

However, I suspect you will find my experiment works as I said at least for things near the subject. Now you mewntion the change of magnification of the OOF object, I need to go and try a more elaborate experiment..I'll try to press the shutter and post some pictures this time!<br>

In my raytrace, I adjusted the field angle to maintain the magnification and may have inadvertaintly cancelled out the effect you mention. Thats always the risk with fancy software!<br>

Some of my portraits are in my portfolio here, taken on 5x4 at f2.5 or f4 and you can easily see the dramatic effect of format size. If you print these photos at a decent size the effect is eye popping. Theres no F0.7 lenses on offer, so this is the only way to get this effect at any cost.<br>

Whether its a good effect is up to the viewer. I just find it a bit different and interesting, not necessarily better than the usual arrangement.<br>

Of course there are other advantages of a human interaction type associated with an huge and interesting looking camera that take 10 minutes to set up for one shot. I dont have a problem making my subjects relax. Usually the opposite - they get bored after 3 or 4 frames!</p>

<p>Kevin</p>

<p>I did some sums, and I also tried out a few lenses and tried to work out the effect of focal length on background blur. My conclusions seem to be at odds with the conventional wisdom so I wanted to check that I havent got it wrong.<br>

So most people say that longer lenses are better for selective focus and blurring of background detail. I think this is wrong _IF_ you keep the subject size the same in the frame at all focal lengths and for the same Fstop. This means that you stand farther from the subject on a longer lens.<br>

When I tried this with a 50mm and 200mm lens there was (almost) no difference in the blur of an object a little way behind the subject.<br>

I have given a lot more detail <a href="http://wideopeniris.blogspot.com/2011/01/which-lens-blurs-background-best.html">here</a> where my tone is more definite - of course I could be completely off the mark and am happy to ammend my thinking if its seems that way!<br>

I hope this isnt too controversial (ducks..)</p>

<p>Kevin.</p>

<p> </p>

<p>Thats a pretty machine. Much tidier than mine. As I said its a bit warty- there are alot of 'zeiss bumps' under the leather and several worn corners. The paint is chipped and the camera has the air of many years hard labour. The shutter is really worn out. There is more and some photos here:<br>

<a href="http://wideopeniris.blogspot.com/">http://wideopeniris.blogspot.com/</a><br>

This camera is from before the ross era. I have yet to acquire an ensign with a ross lens. My autorange 220 also has the ensar. When stopped down to f8 or smaller its indistinguishable from a tessar - quite sharp to the corners and similar contrast (same number of air- glass interfaces). I'm expecting this one to be less contrasty as it has no coatings.<br>

Kingslake gives the field of a rapid rectilinear as about 50 degrees - and the cooke lens at around 45 degrees although its all a bit subjective depending on how soft you can tolerate the edges. So likely to be similar.<br>

Kevin.</p>

<p>Partly out of curiosity and because I like to tinker with cameras as well as use them, I bought a Houghton Butcher Ensign Autorange 20. This is a 120 roll film camera with coupled rangefinder from the 1930's - its a bit warty and it had shutter troubles (another matter - the 'mulchro' is just worn out really).<br>

strange thing is it has rise and cross slide movements. Now the lens is a triplet 100mm F4.5 Ensar Anastigmat. It must have a coverage barely capable of covering the 6x9 film area even stopped down. So why does it have movements too? Any ideas? How are you meant to know (there being no ground glass) where to set them to?<br>

I cant see why you would want them on a camera with this lens! But they went to a fair amount of mechanical trouble to provide them.<br>

Grateful for any insights....<br>

Kevin.</p>

<p>Craig: The shutter on my speed is a travelling slit type of shutter that is not fully open at any point of its travel, even at its slowest speeds. There are flash contacts, but these are designed to work with FP flash bulbs that light for a long time (something like 0.5secs) - such flash bulbs are now almost unobtainable.<br>

Also the lenses I use have 4 - 5 inch diameters and there is no practical leaf shutter for them at any price. There are very large shutters by fairchild from 1950's aerial recon but they weigh lots and are much too big to fit (not to mention being as rare as rocking horse droppings)<br>

So continuous light seems the only answer for my rig - I just would like to avoid frying my subject.<br>

Having now shot a couple of test sheets of Ort25 from ADOX, I have also established that its true speed is even slower, with 16ASA being right for a good contrasty neg., so even more light needed, even at f2.8 - f4 which is what I use for the narrow depth of field.<br>

Mark: Kino Flo are way beyond my budget. The Photoflex lamps look similar to others I've looked at, and their three bulb head looks good, but again it looks rather expensive - its obviously designed to cope with 3kW of tungsten. How did you find the colour rendering?Were you using multiple lamps in the box?<br>

That much light would be fine for the shooting HP5, but I guess the ADOX would be a big problem. Maybe I best stick to using that outside!<br>

Many thanks for all your help,<br>

Kevin.</p>

<p>Hello,<br>

I have been shooting my 5x4" speed graphic for portraits using fast lenses for a while. Up until now I have used available light from a window and the modelling bulb of my flash heads to provide a little fill. This still requires me to uprate the HP5 to 800ASA to get enough light.<br>

I'd like to use a slower film and that means more light. I cant use flash, because the lenses I use have no shutter and I am using the focal plane shutter. Short of using FP flash bulbs and large cost and poor availability, what are my options?<br>

I'd like to avoid hot lights like tungsten, but have seen that you can get flourescent based lights with about 6000 lumens per lamp (100W lamps equivalent to about 500-600W tungstens). Has anyone got experience of using these for portraiture?<br>

Mostly I am shooting head and torso due to the wide field of the lenses, at a distance of maybe 3 - 5 ft.<br>

Always black and white so colour balance not too important, although I do plan to try Ortho films so colour may be an issue....<br>

any experience of using these sort of lights appreciated.<br>

Kevin.</p>

<p>So if I read that right - I need to set ISO 25 on my (pan sensitive) meter and meter as normal without a filter, and yes maybe it should be iso 50, who knows... have I got that right?</p>

<p>Thanks,</p>

<p>Kevin.</p>

<p>I have a box of Adox Ortho 25 ASA sheet film for 4x5in. I am wondering how to meter it.<br>

Does the rating of 25ASA account for the fact that the meter is white light sensitive, but the film is blue sensitive only? In other words, do I need to put a cyan filter (an 80c is the closest I have) on the meter to get it to meter correctly (with it set to 25ASA) or do I meter with no filter (perhaps making adjustments for strongly coloured scenes) and set to 25ASA ??<br>

many thanks for any advice,<br>

Kevin.</p>

<p>I have one of these lenses, exactly same spec except for slighly different FF -mines mounted in a shutter, so the FF might be different (I presume your BF is 18.838 not 8.838 inches). They are for aeriel rconaissance with 9x18 inch film. The image circle is >600mm in diameter.<br>

I have tested this lens for radioactivity using a geiger counter and it is cold. As far as I can tell it is a four element tessar design, with rear cemented pair and two seperate elements in front. I've looked at the aeriel image using an eyepiece with high magnification, and the image is impressive. I suspect that it is APO, since there was negligable chromatic abberation.<br>

I bought mine for the fairchild shutter it is mounted in, with a crazy idea to fitting it to my 300mm F2.5 Aero Ektar cells ( I have a pair of cells and no body - if anyone has a barrel for them that would be good!). Only problem is I cant get the lens off the shutter, so I may well turn it into a 6 inch refractor telescope when I get time to do the engineering!<br>

Now the Aero Ektar is radioactive - 650cpm at 6inches and the colour of a good cup of tea - I've yet to try the UV BLB tube on it....<br>

Your lens cap is probably from the 24" Kodak aero-ektar that comes up occasionally on ebay.<br>

I paid $25 for my B+H on ebay (and considerably more to get it to the UK) so they arent that valuable - cant imagine how much it cost to manufacture!<br>

happy playing,<br>

K.</p>

<p>If you want a fast lens for portraits with shallow DOF, I'd recommend a longer focal length - I have a pentac f2.9 which is quite sharp wide open in the centre and still pretty good at the edges- easily good enough for portraits wide open. Bokeh is very nice indeed, with little mechanical vignetting<br>

I have an aero ektar too 178mm f2.5 - its very sharp - sharper than the pentac - 100lp/mm at the aerial image in the centre. However it has some Coma wide open and the mechanical vignetting means cats eye highlights in the bokeh that are quite distracting. Also its twice the weight, much bigger and doesnt take standard filters (it has no threads)<br>

The pentac takes standard 77mm filters (or 67mm on the rear). Mine is single coated and seems to bee a good one, 60+lp/mm wide open- quality can be variable so you'll want to try it out.<br>

Both lenses show very good performance at f4 - the AE's coma and vignetting go by f4.<br>

At these focal lengths its easier to get a good head and shoulders without being in the subjects lap. At 135mm you are going to have alot of the environment in the shot.<br>

For portraits, where you keep the size of the subjects fixed, the DOF is only affected by the f no. and the size of the negative, being proportional to both. So any focal length f2.8 lens gives the same DOF if you frame the subject the same in each case.<br>

Beware, though of focal plane errors in your groundglass, as tiny errors are important. I suspect many lenses have been decalared poor performers by people with misaligned GG or holders. The accuracy needed at f2.5 is a tolerance of 0.1mm or less.<br>

K.</p>

<p>The question wasnt about film per se... no one has mentioned that with LF you can get narrow depth of field. Can someone find a 30mm F0.4 lens for my aps digital camera ? - On LF I have my 210mm pentac f2.9 and my aero f2.5 178mm.<br>

Add to that the fascination your subject gets about your unique looking camera and its long history ( a 1947 speed graphic in my case) and you get a totally different experience of portraiture. The 10 minutes it takes to setup means I have time to chat with my subject and they relax because they forget about being photo'd and whether they're hair looks ok etc.<br>

Also I concentrate on my shot, taking good care of exposure and composition because I know it must be right.<br>

Regards film vs digital? Its what works for you. I scan my negs on a flat bed scanner - no enlarger or darkroom needed, but I still sit in front of the computer. On the otherhand, the scanner is capable of superb quality and resolution without spending $$$$$ and if my hard disk crashes, I have the neg for ever.<br>

Thats what makes it work for me.</p>

<p>I'm travelling to San Diego from London next week and I'd like to take my Speed Graphic to its home country for a few cityscapes etc.<br>

Given the trouble of getting film through airport security and back un-harmed, I'm trying to find out if I can buy and develop the film in San Diego.<br>

Does anyone have a place they use in the city that I can trust to develop a grafmatic full of 5x4 in a few hours ? (time is short, and my photo opportunites are the day before return...)<br>

many thanks,<br>

K.</p>

The question of bokeh is a matter of several things. It depends alot on whether you stop down or shoot wide open.

Stopped down the AE is both very sharp and has very good bokeh before and after focus. SA is very well controlled, so no donut bokeh. The iris has many leaves so the bokeh is nice and creamy. The AE can be a very good lens in this situation even close to the subject.

Wide open introduces some more issues. My experience of the AE is that there is alot of mechanical vignetting and this spoils any point highlights in the corners or edges of the frame making them cats eye shaped. In addition there is some Coma wide open and this is seen as a bright edge on the cats eyes making them rather distracting. By F4 both disappear so if you still want shallow DOF then F4 is good.

For portraits, the COMA and Vignetting arent a problem as long as there are no point highlights, but you ought to avoid these anyway.

My Pentac 8inch F2.9 has better performance wide open except that there is a little SA so behind highlights are slightly bright edged (only a little) and not as good as an AE _except_ that they are more or less round all across the frame. The pentac is not as sharp.

My AE (EE vintage, yellow dot) is 100lp/mm or better at the aerial image, giving >60lp/mm on 100ASA B+W film. The Pentac is about 40lp/mm on film in the centre. The pentac is alot less sharp at the corners of coverage but still good enough for 4x5.

I have a few of my portraits in my gallery shot on the AE at f4 or wide open. They have a nice glow, although the contrast of the AE isnt that good. The Pentac (mine is single coated) has better contrast.

K.

Hello,

Can someone tell me what the color space transformation functions typical are,

and whether they are commutative. I.e.:

If I have two devices that have a color mapping - say a printer and a scanner..

If I map P * S (which is what you get if you scan a printer output), is the

mapping the same as S * P (which is what you get if you print a scanned image)

Also, how good are color flat bed and film scanners in terms of their color

mapping - is there significant color mapping required or is their gamut much

wider than that of typical printers?

My questions are regarding the possibility of being able to calibrate the (not

quite mainstream) process of scanning slides on a scanner and producing prints

from a printer - the hybrid film/digital method - please no flames/hijacks on

the suitability or utility of this technique - lets stick to the technical

questions!

If the processes are communatative then it should be possible to calibrate the

process by printing a known digital color map and scanning the resultant

print.The scan-print route would then be to turn off one of the management

steps and use the P*S transformation to correct the other. Trouble is I dont

know enough about color management to know the sorts of eqautions used in

mapping profiles.

many thanks for any answers.

Kevin.

You should also meter through the filter. Otherwise you are metering a whole load of light that isnt going to be there when you open the shutter. I find good consisitency with a fixed ISO for a given filter and my whole roll comes out with good density.

Procedure is:

(1) Filter off

(2) compose scene in viewfinder

(3) evaluate scene contrast to make any adjustment to expected exposure (e.g. if theres loads of leafy plants, and we want them white then add 1.5 stops to get the meter reading right - this is just the same as normal photography where the meter wants to make the scene mid tone - try shooting a white wall using just the meter reading - it'll be gray in the shot.)

(4) focus using the viewfinder or AF

(5) adjust focus using the IR focus indication on the lens

(6) filter on and meter

(7) make any adjustment to exposure from (3) and shoot.

When handheld, you need the filter on really, and peering through an R72 filter is tough - an eyecup (the sort that glasses users have) will help block out unwated light in the viewfinder window so you can let your eye adapt to the dark image. In these cases I tend to focus by dead reckoning.

Ofcourse if you are still not sure what speed to set ehn you will need to bracket as well.

How did you get on with your roll of SFX? I've just bought a roll for my first go at it. I imaging from the response curve that it will be similar to the other 820 variants.

Kevin.

The matter is all in your meter. Kodak HIE is rated ASA 200 for TTL metering acording to the kodak datasheet. This information, however is utterly useless because your camera's TTL meter _will_ have an IR block filter. Your cameras manufacturer has diligently put it there to stop the meter in your camera being confused by high IR levels in some scenes, so that your normal film is exposed correctly.

Because different cameras have different filters, you must determine yourself what the 'effective' spped of the film is in your camera. A high end camera will have a better filter, so its not even clear to divide cameras by manufacturer.

Because the TTL meter is a bit 'deaf' to IR light, you will need to _increase_ the ASA/ISO/EI/DIN settings on your camera (these are all types of film speed standard btw). I Prefer ASA so: Kodak says 200 ASA, but if you use an IR filter that is opaque (or very very dimly red) like the Hoya R72 or other 720-750nm filter you may find you camera is 5 stops or more deaf.

On my canon A-1, 6400ASA needs to be set. This is because the meter thinks that there is 5 stops less light than there actually is because of its filter. Your canon A-1 might be different due to tolerances, but not far out. Other cameras will need a different offset. HIE is very sensitive indeed, and with the right settings hand held shots are no problem on bright days. The other films are _much_ slower and have less response in the longer IR, and so you may find they need a tripod in bright conditions.

For your first HIE start at 3200ASA and bracket +/- 1 then +/- 2 stops. This will give you an idea of your meters sensitivity. If you change filter then you have to start again. With a 25A filter (red) on my canon, I use 800ASA, becuase the 25 lets alot mre light through to which the meter is sensitive , although you get a weaker IR effect with skies no longer black.

So you have to use trial and error, with a starting point based on normal experience. So set the ASA form the datasheet and add 5 stops for a black filter or 2 stops for a red filter for your TTL meter and then bracket you first roll.

That recomputation is needed is expected. Pretty much there is a glass close to the old types, so adjustments are small. Schott, for instance have brought out many new glasses (n- types) which meet current legislative requirements. Also some interesting designs have troubles like radioactive glasses - the new lens, re-computed from the same formula with modern glasses, would not have these 'worries'

There seems to be many companies offering custom lens grinding services and competition there is enough to make prices less than impossible. The problem is one of paying for tooling costs which must be absorbed over the life of the product.

I guess one reason for this thread is to try to gauge how many people who use 5x4 or 10x8 gear (or larger) would like to buy new lenses - hassle free, at medium prices (cant compete with schneiders and rodenstocks, but maybe less than cooke - about the level of congo for instance).

Any company starting down these lines would have to concentrate on the most popular of the 'hard to find' old lenses, like the xenotars and planars and offer only a few products to begin with, much as Cooke have.

Kevin.

Its not prize winning perfection that is the goal here, but offering the particular behaviour of older lens designs for creative use, but in clean new and reliable forms that are easy to mount and might benefit from modern coatings if desired.

There are plenty of 'perfect' lenses for those who desire the optimum sharpness across the frame, but there are plenty who want wide open performance or controlled and predictable abberations for a particular effect.

Kevin.

Alot of people are interested in the image properties of older lenses on large

format cameras, and I was wondering if there would be a demand for new lenses

manufactured to high qulity but using old lens formulas for their unique image

forming qualities.

Because these would be low volume products, they would not be cheap compared to

the cost of a used lens for the more common lenses, but it would be possible to

buy in new condition the lenses that are very rare or impossible to find, so in

some cases it might be an economic purchase as well.

In addition to reproduceing the 'old masters' of optical designs, it would also

be possible to bring modern coating technology to these old designs to improve

contrast and flare resistance without destroying the intrinsic qualities of the

optical formula. Also mounting options could be improved with lens mountings

tailored for modern shutters.

So how many of you would want to buy such a lens and what old lens designs

would be most desirable?

Kevin.

Just to make my point finally:

Normal Lens:

Normal means - gives normal perspective on a print viewed at normal viewing distances.

Nothing to do with - the normal lens for that camera or normally sold with etc etc

My favourite definition come fom dan stella:

..that a normal lens is second best for any particular purposes..

http://www.dantestella.com/technical/lenses.html

cheers

Kevin.

Sorry Guys,

But the answer is "a, b and c are all correct" to a certain extent.

The basic answer is that the angle of view of a 'normal' lens is similar to the average angle of view subtended by the macula - this is the part of your eye that sees fine detail (a).

This happens to roughly coincide with the diagonal of the film (b) in many formats, but not all (try 6x17 for instance!).

If you present this angle of view then perspective is correct for a print viewed at normal viewing distances (this is the VITAL point - forget your viewfinders). The viewfinder attempts also to cover your macular field of view and thus has normal perspective when viewed through a 'normal' lens

The assertion about digital cameras needing 50mm standard lens is incorrect. In many APS-C digital cameras the angle of view of the viewfinder is small (and dont they look pokey! I much prefer my Canon A-1 viewfinder to my 10D) and this is partly an optical design problem. The viewfinder magnifications are thus different to 35mm cameras.

A print viewed at normal viewing distance shot with a 50mm lens on an aps-c sensor will have short tele perspective (which is why I use my 50mm 1.4 as a portrait lens - a bit cheaper than an 85mm F1.2 L on film!) - the 'normal' lens for an APS-C DSLR is about 30mm

Kevin.