Category Archives: Analogue

Focal length, explained.

When we talk about focal length in photography, what we are actually often talking about is the field of view: How much of the world in front of the camera is captured through the lens. Some people also talk about magnification, but I will not go into that here, as it relates to macro photography more than focal length.

Focal length can be described as the distance from a pinhole to the (film) plane behind it. Drawn below is a simple version of a camera, the camera obscura – or pinhole camera. When light passes through the pinhole, the image on the other side is flipped upside down and mirrored. The same happens in a camera lens and in the human eye.

perspective

The further away from the pinhole, the film plane is placed, the narrower the angle that the light travels through the hole in will be. This means that the field of view gets smaller and the image on the plane will appear more magnified. Move the plane closer to the pinhole and the angle gets wider and more of the outside world will be represented in the plane. The image below shows the angle the light travels in through the pinhole.

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When we talk about focal length, we often talk about it in 35 mm terms. That means we are talking about the field of view, you would get on a single 35 mm film frame put in the center of the back plane of a pinhole camera.
This means that when we talk about focal length, we need to know which format the recorded image will be in, otherwise, we cannot know which field of view, we will actually get.
The image below shows a front view of an image hitting the plane of a camera obscura. The dashed boxes show three common image formats in correct aspect ratio. The 6×6 medium film format, the 35 mm film frame, and the micro 4/3 format, common in mirrorless digital cameras, such as the Olympus lineup.
The image here shows us how big a difference there actually is between the different formats and WHY we have to be aware of crop factor – the factor of which the diagonal of the format is different from that of a 35 mm frame (which is crop factor 1).
The 6×6 image has about a 1.55x longer diagonal than the one of the 35 mm frame and the diagonal of micro 4/3 is 2x shorter.
Probably the most common format today in digital SLR cameras is the APS-C format. The crop factor here is 1.5x or 1.6x smaller than 35 mm depending on the manufacturer of the sensor. I have not drawn it on the picture below, to avoid it being to clotted.

formats

Today, lenses are made specifically for all the different formats, but one thing remains the same – what the focal length written on it represents. The distance the light would have to travel in a straight line before hitting the film plane and gives the same field of view as the lens in question does on the given format.
This means that a 50 mm lens on a micro 4/3 camera gives the same image as a 100 mm on a 35 mm full frame and the same as a 155 mm on a 6×6 frame, when we talk about resulting field of view on the frame.
An example: A popular lens for the micro 4/3 format is the 12-40 mm zoom lens. This gives you a field of view corresponding to a 24-80 mm zoom lens on a full frame camera.
So, you always have to multiply or divide the focal length by the crop factor of your system, to get to a common place to talk field of view from. Multiply if your format is smaller than 35 mm and divide if it is larger.

Stand development of pushed and pulled film

Pushing and pulling film are techniques to get more out of the film than box speed allows.
Pushing means shooting and developing as though the film was a higher speed (ASA/ISO) than rated by the vendor. And pulling is the opposite, shooting and developing as though the film was slower than rated.
How this is achieved, is really simple. The film is either under- or overexposed by the number of stops required to achieve the desired film speed. E.g. by underexposing a 400 ASA film by one stop, you are actually pushing the film to 800 ASA – if you remember to develop the film as though it was an 800 speed film. And likewise, if you overexpose a 400 ASA film by one stop, you are pulling it to 200 ASA, if you develop accordingly.
This is possible because the latitude of a modern film emulsion is quite large – much larger than what we see in digital sensors. And most vendors will tell you, how much your film can be pushed or pulled while retaining an acceptable image quality. Typically about two stops over and under the rated box speed.

Now, this is quite cool, if you require a higher shutter speed, but lack the light when shooting at box speed – or require a shallow depth of field and a slower shutter speed for motion blur but have too much light. The downside is that you have to shoot the entire roll of film at the same ASA speed – if you want to develop traditionally that is.

This is where stand development comes into play. Stand development is basically a development method where you let the development tank “stand”, meaning you leave it alone for the majority of the development time.
For this to work, you need a thinner dilution of developer than usual.

I use a 1:100 dilution of Rodinal (R09 One Shot) for my stand development. I let it sit for about an hour, only agitating for the first 30 seconds, then stop and fix as normal.
Now, the theory is that, if you do not agitate, the developer will go to work on the highlights the fastest as they are the more sensitized. After a while the developer sitting next to the highlights will exhaust and “protect” the highlight areas from overdevelopment. The shadow areas, though, will continue to develop for as long as they need according to their individual levels of exposure.
Because stand development works this way, you can actually push and pull images throughout the entire roll of film and still have usable negatives on all exposures.

I did a small test to demonstrate that you can actually shoot one film at different exposures and get nice results on all images. The test is not perfect because the light changed a little because if moving clouds and I wasn’t on a tripod, so focus changes a little from image to image. The film is Ilford HP5+ box rated @400 ASA.

pushpull
These five images were shot immediately after each other. 0 is the correct exposure according to box speed and the others indicate the number of stops over- and underexposure. These have not been corrected individually.

After scanning, I pulled the images into Adobe Lightroom and did an autocorrection on “0”. Then I synced the settings to the other four images, so you can see the immediate difference.

pushpull-corrected
These are the same images as above, but all have been individually autocorrected, so you can see the difference in the final results.

Below are the images in a larger size for inspection.

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‘-2’
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‘-1’
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‘0’
20160215-raw0004-blog
‘+1’
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‘+2’

Negative scanning – thoughts

In this day and age, shooting film will most likely include scanning the negatives to use them for print or web. A lot of different scanners are available to do the job. From the cheapest one click scanners to high quality, high priced professional drum scanners.

In this post I will talk a little about my experiences which are, admittedly, limited. This is what I have learned so far.

I currently work with a Reflecta CrystalScan 7200 dedicated 35 mm scanner and before that a Canon Canoscan 9000F mark 2 flatbed scanner.
The Canon promises a resolution of 9600 dpi. But optically it can only deliver about 1700 dpi. The Reflecta promises 7200 dpi but only delivers about 3800 dpi.
Now why the difference in resolution? Well, the 9600 and 7200 dpi describe the precision of the motor, not the scanner optics. The 1700 and 3800 dpi are what the scanners optically can deliver. This number is what you have to look at when you choose a scanner.
The whopping 9600 dpi of the Canoscan 9000F mark 2 are really useless because the optics only deliver 1700 dpi, so even if it sounds great, it’s really not.
The Reflecta delivers 3800 dpi which is fairly good for the price range it is in.

Below, you can see a comparison between the two scanners. Same negative scanned on the Reflecta and the Canon – shown in that order. As you can see there is quite a big difference in sharpness. The Canon is very soft and on the Reflecta, you can make out the grain, quite easily.
Now, to be fair, I have to mention that I used to different programs to do the scans. The Canon scanned using SilverFast SE and the Reflecta using Vuescan. According to various tests, Vuescan is supposed to be the better of the two, producing higher quality results. However, the  difference in quality cannot be blamed on the software entirely. The scanner itself is probably what makes most of the difference.

 

raw0001 copy

This is a full view of the negative for reference – made from the Reflecta scan.
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Now, I have learned from reading and talking to people, that even if the scanner only optically produces a certain resolution, you should still scan at as high a resolution as possible and then use an image processing program to reduce the size to match the optical resolution of the scanner. The reason for this is that you have to make sure that the scanning motor is working with enough precision to achieve the highest possible optical resolution. Now, how this looks at 100% crop differs from scanner to scanner. The Reflecta produces something like this – as you can see the edge is very pixelated. When you reduce the size to match about 3800 dpi, the pixelation should disappear:

Screen Shot 2016-01-30 at 22.09.25

 

Here is a 100% crop of the image resized to match the Reflecta’s 3800 dpi:raw0001-2 copy

And here is a full view of that image:raw0001-2-blog

I am still quite new to the whole scanning thing and I am certainly still learning. I will be posting about it as I learn more, but for now, I hope this was useful to you.

Quickfix for lens adapters for Canon EOS cameras

My main digital camera is a Canon 1Ds mk2. It’s a full frame camera from 2004, I believe. I have grown fond of using vintage manual focus lenses on it. Mainly Nikon F mount lenses, but also a couple of M42 lenses. That is all fine and dandy with a cheap adapter from Amazon or Ebay. Or so I thought.
If you get an adapter without focus confirmation and have an older EOS body, you might run into a little problem. But before you get to modifying your adapter, test it. If it works, modification is a waste of precious shooting time.

_MG_2425-blogOn older EOS digital bodies – probably also on EOS film bodies, there is a little pin on the left side of the lens mount. When you mount a lens or an adapter, this pin is pushed up. For some reason though, it has to be able to move down when something without a focus chip is mounted. But the flange on the adapter prevents that. If you try to shoot your camera with an adapter mounted, the mirror will open and then lock up and you have to switch the camera off and on again for it to pop down.

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To solve this, I actually filed off a piece of one of the flanges, as you can see on the pictures above. Now, which flange do you file? Answer: The one on the opposite side of the red EF-mount dot, as you see.

When you have finished filing your adapter, make absolutely sure there are no metal filings or metal residue of any kind left on it. If it gets in your camera, it can mess up quite a few things. If it is a digital camera, it can damage your sensor severely. I had a piece of metal get stuck by the lens contacts which caused my mirror to jam, just like what happens if you don’t file the adapter. This happened while I was using a fully automatic AF lens, so needless to day, I almost pooped myself, thinking my camera had broken. Lucky for me, when I popped off the lens, a piece of metal filing fell out and all was good again.

Zorki 4 shutter problem

_A1P0176I recently got my hands on a Soviet Leica clone, the Zorki 4. There are many different versions and I believe mine to be version no. PM1800. That is not really important, but always nice to know what you have. See link at the bottom for more information about this.

There is one important thing about the Zorki 4 – before you change the shutter speed, you MUST cock the shutter. Otherwise you mess up something internally in the shutter mechanism. Lucky for me, I had a friend tell me that before I had a chance to break my new camera. So I made sure to cock the shutter, then change shutter speed. What is important to know here is that the shutter speeds are divided into two categories. The fast and the slow. The slow shutter speeds range from 1 sec. to 1/60 sec. and, with the exception of 1/30, use a governor to time the delay, the shutter is completely open. The fast shutter speeds (and also 1/30) range from 1/125 sec. to 1/1000 sec.  and does not make use of the governor. The bulb mode does not make use of the governor either, since it is the user who controls how long the shutter stays open. For more information on Soviet shutters, see link below.

I went through all the shutter speeds and at some slower speeds, around 1/4-1/8 sec. it seemed to stick a bit and suddenly, while in bulb mode, the rear curtain got stuck and just didn’t close. I tried fiddling with it in different ways, banging it lightly on the table, etc. to try to release the curtain. But it was just stuck.
I consulted the members of the Facebook group “Vintage Camera Collectors” about my problem and Dan Howard and Mike Eckman of the group provided me with possible solutions to my problem. First was Dan’s solution to what seemed to be the most obvious cause of the stuck shutter: Dirt and hardened grease.

For this you need two things:

  • Lighter fluid like Ronsonol or Zippo Premium Lighter Fluid.
  • Sewing machine oil, gun oil or similar light lubricant. Camera mechanics are very fine precision mechanics, so don’t be using any heavy duty motor oil or something like that.
  1. Take your Zorki, and unmount the lens and the film compartment cover.
  2. Cock the shutter and set the shutter speed to bulb.
  3. Press and hold the shutter button to keep the shutter completely open.
  4. Take the lighter fluid and pour it into both the top and bottom shutter curtain runners. Alan Starkie from the group noted that you should be a little careful not to get too much on the shutter curtains themselves as it might, in the worst case, dissolve some glued assemblies on the curtains – and that will most likely render your camera useless. This, however, is not an issue with the Zorkis as the shutter curtains are crimped rather than glued onto the shutter tapes. But it could present a problem if you try this method on other cameras with focal plane cloth shutters, without knowing how they were assembled.
  5. Let go of the shutter button.
  6. Cock and fire the shutter repeatedly until the curtain move freely again.
  7. Put a few drops of oil in each of the shutter runners and fire again a few times to spread out the lubricant to the entire shutter area. This time, be careful not to use too much as you don’t want excess oil to get on your film or on the back element of your lens.

Now, when I did this – nothing at all happened. It did not work at all. So I set down the camera and began looking into the information, Mike Eckman had provided me with. It was an in depth guide to disassemble the shutter speed selector system in order to fix a pin that is supposedly stuck in the wrong place somewhere. Hours went by before I grabbed my tiny screwdriver set and started dismantling the camera. But I did not get very far because I didn’t have a screwdriver small enough to actually get to the smallest of the screws. Bollocks…
I then started just playing a little with the camera – testing out different shutter speeds, with the rear curtain still stuck. Suddenly, when I fired the shutter at 1/4 sec. the curtain closed as it is supposed to. I fired again, and again and it seemed to work. However the speeds around 1/4 and 1/8 were rather sluggish, which led me to believe that the governor had been clogged up by grease and dirt and had jammed the shutter. Having been rather liberal when administering the lighter fluid (still keeping my fingers crossed that I didn’t mess up any glued parts of the curtains), I am certain some of the fluid made its way to the governor and after a while loosened the stuck parts enough for the shutter to work again. After a few more goes, it now seems the slow shutter speeds are no longer sluggish.

Even though my Zorki 4 seems to work fine now, I would still like to take it apart and do a full cleaning and lubrication of the internal mechanics – but that will have to wait till I have a screwdriver small enough.

Here are a few links related to this article:
List of Zorki 4 editions at sovietcams.com
Mike Eckman’s blog
Information about the nature of the Soviet shutter speed selectors.

Yashica Electro 35 GS battery fix

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The Yashica Electro 35 GS is a rangefinder camera manufactured in Japan between 1970 and 1973. It features a 45 mm f/1.7 lens with aperture range up to f/16. The camera uses aperture priority auto exposure with shutter speeds ranging from 30 sec to 1/500 as well as a bulb and flash sync setting.
The Electro 35 GS was originally designed to be powered by a PX32 5.6V mercury battery, but because of environmental concerns, mercury batteries are no longer produced. In stead a few other options are available. I chose a 6V silver oxide battery, labelled 4SR44. There is also an alkaline version called 4LR44, but alkaline batteries loose voltage when used, which could result in incorrect metering. The battery itself is too small to fit in the camera’s battery compartment, however a quick fix solves that problem.

What you need is:

  • A ruler
  • A utility knife
  • A pencil
  • A piece of rubber tube or garden hose with a 16-17 mm outer diameter. I used a piece of soft 16/12 tube for aquarium pumps bought at the local pet store .
  • Aluminum foil

Now, you need to create an adapter for your battery. The total length of battery plus adapter is going to be 4 cm. The 4SR44 battery itself measures 2.5 cm, so what is missing is 1.5 cm.
Cut a piece of tube 2 cm long. This allows for the battery to be inserted 0.5 cm into the tube. Make sure you don’t insert the battery too far into the tube. It fits very tightly and thus is very hard to pull out if inserted too far.
Take a piece of aluminum foil and curl it up to fit inside the tube. Put the tube on a hard surface, standing up and stomp the foil inside the tube with the back end of a pencil. Repeat this till you have a 1.5 cm long aluminum foil plug filling up one end of the tube and 0.5 cm of free space at the other end. Make sure the foil sticks out just a little bit, so it can connect to the electrode in the battery compartment – but not too far as it might short circuit everything by accident.

_A1P0185Now put the battery into the tube and insert it into your camera’s battery compartment. I prefer to put the + end inside the tube, but you can do it the other way around, if you’d like.

Use the camera’s built in battery checker to ensure everything is connected properly.

That is all. Enjoy shooting your awesome rangefinder camera!

PS: This should apply to all Electro 35 models as far as I know. Please correct me, if I am wrong.