Tag Archives: #largeformat

Still life successes

Using my antique (1900s) large format (10×8) bellows field camera I have been making some successful still life images.

I decided to move away from the uncontrolled variable light of the kitchen window to the fixed lights in my studio (dining room). This removed one variable from the exposure equation allowing me to make reliable test exposures on strips of the photo paper negative I am using. This saves the expense of wasting large sheets of photo paper on improperly exposed shots.

Whilst I am pretty happy that I can measure the light needed with my iphone app based on iso 6 for the paper negative, there are three other variables that come in to play.

1. At larger f stop values (smaller holes in the diaphragm) a small variance in position of the lever or ring setting the aperture has a disproportionately greater effect on the actual aperture used – at f64 on one lens a small tweak can make it effectively nearer f128 – doubling the required exposure time!

2. The bellows effect. Stretching the bellows past the focus length of the lens for close objects decreases the light intensity falling on the negative by an inverse square proportion. Doubling the distance decreases light intensity to a quarter. So 4x the exposure time is needed.

3. At longer exposure times, the longer the exposure the longer you need to achieve a set increase in darkening of the negative. So for a 2 minute calculated exposure I would expose for 2.3 minutes.

With these variables in play it pays to take a test exposure on strip of photo paper before committing to exposing a whole sheet.

For many of the still life images I am using a shorter (8″) focus length lens as this gives the greatest magnification. However it only stops down to f22,rather than the f64 of my other lenses, thus limiting the depth of field achievable. Accepting this limitation I have chosen subjects which do not demand a great depth of field – and am very pleased with the results.

I also added a graduated neutral density filter for the fennel photo to darken the bright base to get a more evenly exposed picture which seemed to work (see bottom photo).

Lens problems with The New Countess

Today was time to take the New Countess full plate camera to Clevedon and try some images of the wonderful Victorian Pier. Shame it was so breezy – not ideal for longish exposures with a huge camera like this one!

With two slides I had 4 exposures to make. It was a good opportunity to try the (supposedly) F384 lens too as it was a good focus length (12 inches – 300mm ) for the job.IMG_2026

Bringing the exposed paper negatives home for developing, I found that the lens I was using – Rapid Aplanat No.3 Ser.D.F.8 (R.O.J.A. vorm. Emil Busch, Rathenow) – was not operating at the indicated F stops – see the title image!

I had tested it in the garden on the pear tree using the widest aperture with no problem – but at the indicated f90 it way over-exposed the image (Paper negative). I tried a couple of other lenses at the same time successfully so thought I’d make some measurements of the diaphragm aperture with digital callipers and calculate the theoretical f-stop  (dividing the focal length by the aperture diameter)

As the F stop numbers increase the variance between the indicated F stop and the calculated one increases greatly. Column headings are Focul length, Diameter (of aperture) in 100ths of an inch, The F stop indicated and the F stop calculated.

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Using a more familiar lens at F45 for a 2 second exposure I achieved a reasonable if (wind) shaken exposure.

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Progress with The New Countess – 10×8 Camera

With some decent weather I have been able to take the “New Countess” into the garden and make some more trial images, testing out the lens and the exposure time variation with extending the bellows.

I am pleased to find that the combination of light metering with the I-phone app “Light & Exposure Meter” and adjusting for the bellows extension using measurements from “QuickDisc” (www.salzgeber.at/disc/)I was pretty successful with the images I made today. As always I like to push to the extremes – so after the pears image, some extreme contrasts with bright white table and chairs and then deep shadow for the surround of the bust.

I clearly have some work to do on managing the higher contrasts. I think I might have to expose for less and develop for more time. Anyway I am so pleases with the look and feel of these images from this camera. The Pears were shot at f11 and the table & chairs at f22. The bust was also f22 as I wanted to have a greater depth of field, but this wasn’t as deep as I had hoped – so will try again with f64.

NB – The images displayed here were made as paper negatives then digitised and made positives in Photoshop. The glossy Ilford paper was treated ISO6 and pre-flashed with an enlarger to reduce contrast.

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Refurbishing Antique Bellows Cameras

The Blog writing has been on the back burner whilst I spent time refurbishing my two 1900s, mahogany and brass bellows camera.

The Boots camera is a single-rack camera and less useful so I decided to refurbish this one keeping it as original as possible. The Hora camera is slightly more modern by 10 -20 years and has a double rack and pinion adjustment making it much more useable since focussing can be accomplished without changing the distance between the lens and the object. This Hora camera then was to be refurbished to make it as useable as possible.

Each camera was stripped down, as far as possible, to its component parts. IMG_3023  The wood was cleaned with “Soft Finish” remover to gently lift off grime leaving the patina intact. The wood was finished with liquid wax. All sliding surfaces had a light dressing of graphite powder to ease movement.

The brass was in a badly corroded state in many places.

The worst was treated to a light sanding with 600 wet&dry then polished with a cream cleaner. After completing the first camera my fingers hurt so I purchased a battery powered Dremel to do the buffing. However this new Dremel was dreadfully underpowered and stalled with the lightest pressure at the slow and medium speeds. After finishing the cleaning using the high speed only I returned the Dremel to Amazon who refunded me fully.

As the pictures show the bellows of the newer, Hora camera have had a lot of bookbinding tape applied to cover light leaks.

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I bought, from a supplier in China, replacement bellows and glued them in place with flexible adhesive. Whilst the new bellows are fully light tight they are less stiff that the original and sag quite a bit. To address this I have attached a brass ring to the middle section of the bellows and use a tensioning wire to hold the bellows up. This is a period feature on some other cameras of this type.

The Boots camera had its glass screen cleaned with 1200 grit wet&dry carborundum paper. I still haven’t removed all the marks, but the glass is much clearer in use. It does still need new bellows but I want to locate a leather type to look more original than the Chinese polyester version.

Both cameras have now been completed.

because of the cleaning and lubricating graphite, are much easier to use. and I have taken some very pleasing images with them since the refurbishments, an example of which is below. More images to follow in my next blog.

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