There’s a lot of confusion when it comes to using lenses designed for 35mm cameras on the current crop of Digital SLRS. Many photographers have sizeable investments in 35mm lenses for their film cameras, and for the most part their lens investments drive them towards a particular digital camera body, whether it’s Nikon, Canon, Minolta (Sony), Pentax or Olympus.

Luckily, all the manufacturers retained their old AF mounts, except for Olympus, which uses the newly designed Four-Thirds mount. Sony retained the Minolta ‘A’ autofocus bayonet mount for the Alpha series cameras, allowing all the fine 35mm lenses out there since 1986 to be used. The same goes for Nikon and others.

However, due to cost constraints at the present time, most digital SLRs use a sensor that is smaller than the 35mm format size of 36mm x 24mm. This smaller format is 22.7mm x 15.1mm, and is known as the APS-C format. Sony and Nikon (and others) use a sensor size that is approximately the APS-C format size. As can be seen, the APS-C size provides a much smaller image area, 342.77 square millimeters versus 864 square millimeters for the standard 35mm format.

When a 35mm lens is used on the current crop of digital cameras, the smaller sensor size means that the 35mm lens will now have a narrower angle of view (also called FOV or field of view) than when used on a 35mm film camera body. This is due to the fact that the 35mm lens creates an image on the film (or sensor plane) that is is sufficiently large enough to cover the 36x24mm frame it is designed for.

When used in a Digital SLR that has a smaller sensor (and thus image size), the image formed by the 35mm lens is still the exact same size as before, but the smaller sensor can only use a portion of it. In effect, this constitutes an “in-camera” crop. This cropping is determined by the ratio of the sensor size to the 35mm format size, distance of the image plane from the front of the lens etc.

In most of the cameras using APS-C size sensors, the ‘cropping’ is equivalent to using a lens that has a narrower angle of view (telephoto effect). This Crop Factor (also known as Focal Length Multiplier) is around 1.5x (Sony Alpha) 1.6x (Nikon). In some cameras, Canon uses a sensor size that is slightly larger, which gives a 1.3x factor (this is the APS-H format). The Four-Thirds system used by Olympus and Lumix (Panasonic) has a 2x factor.

The focal length does not really change, of course. The smaller sensor’s ability to register only a portion of the total image causes an APPARENT increase in focal length due to the cropping. This has the effect of using a lens with a narrower angle of view, the same as using a telephoto lens. (Luckily, the sweet center portion has the sharpest part of the image).

The image edges which may not be sharp, or have aberrations are cropped in-camera. For the user, it’s easier to remember by multiplying the focal length of the lens they are using with the factor for that particular body, and that gives us the APPARENT focal length.

A lot of the confusion can be eliminated by using the term APPARENT rather than EQUIVALENT. for example, on my Sony Alpha 700 (which has a 1.5x multiplier for 35mm lenses), it would be more accurate to say that my Minolta 50mm lens has an APPARENT focal length of 75mm, rather than saying my Minolta 50mm is EQUIVALENT to 75mm.

This apparent increase in focal length does not affect the aperture, so the APPARENT focal length of 75mm is still at a fast f/1.7. This will serve as an excellent portrait lens, since it can frame head and shoulders perfectly, but you’ll find yourself having to move back when you want to include more of the scene.

For most wildlife photographers, birdwatchers and even landscape photographers, the apparent increase in focal length can be a unexpected blessing – they get more ‘bang’ for the buck from their existing lenses. When coupled with the higher ISO capabilities of DSLR cameras and in-camera image stabilization that will let them handhold the camera in situations that would have required them to lug along a heavy tripod.

If you’re using a MACRO lens, such as, for example my Sigma 50mm f/2.8 (a very sharp lens with a true 1:1 macro capability) the apparent increase in focal length permits the macro subject to be fill the frame without moving in as close. Since the stand-off distance is greater, more light can reach the subject. The increased distance also helps when photographing skittish subjects that are likely to fly or hop away if approached too closely.

When the subject is framed in the Sony Digital SLR, it is seen that the Depth of Field is greater for the same magnification when compared to using the lens on a 35mm film camera like my Minolta Dynax 800si. This is a great advantage for macro-photography where depth of field and subject lighting are always problematic.

The whole situation is different when it comes to wide angle lenses. This is where most photographers are ready to burst into tears. The 1.5x or 1.6x multiplier effect holds good on the wide angles too, and this means that a normal wide angle like 24mm lens which would give a 74 degree field of view on a 35mm format camera will now only provide a FOV of 62 degrees or so, approximately that of a 35mm lens. In the same way, an ultra-wide 16mm becomes an apparent 24mm a 28mm is an apparent 42mm and a 35mm lens behaves like a 52.5mm normal lens.

Given the fact that most wide angle lenses are EXPENSIVE, no photographer would like to see his investment reduced to a moderate wide-angle or a normal lens. However, such is life. You win some, you lose some. To get a true wide angle on the Sony Alpha 700, I would have to invest in a 18mm to get 27mm (luckily, that’s included in the zoom range of my Sony 18-200mm lens that I bought with the camera). Since the 18-70mm is bundled as a kit lens, most owners will have at least a 27mm wide angle, albeit a slow one).

To get the 24mm, we’d have to invest in the very expensive Sony 16-105mm Zeiss coated zoom lens (apparent focal length 24- 157.5mm). Buying a faster wide-angle prime lens would be prohibitively expensive for any amateur, and even professionals would hesitate.

My advice? If you really need to shoot wide angle, just use your film camera. You can still buy a fine Sigma 24mm f/2.8 AF at a reasonable price. The Sigma 24mm is a good deal, since it had a matte black Zen finish that tended to flake off, giving the lens a “very used” appearance and usually marked down. This is just cosmetic, and does not affect the lens performance in any way.

The same Sigma lens was re-badged and sold by Ritz as their house-brand Quantaray lens, but with a different, more durable finish – but it’s still the same lens. Don’t be fooled by the appearance of either lens – this is a very high quality lens. Besides, you can always use the Sigma on the digital SLR as an apparent 35mm f/2.8 prime lens in place of a ‘Normal’ lens. You’d pay hundreds more to get a similar “designed for digital” Nikon, Sony or Canon lens.

Of course, all this talk about crop factors and multiplication factors will become moot when Full Frame digital SLRs become common. Canon already has one, and Nikon and Sony will follow shortly. In fact, I would not be surprised if the Sony Alpha 900 was not released in a few more months. When that happens, lenses will behave as they were designed and there will be no more confusion.

As for me, I rather like the fact that my Tamron 70-300mm now behaves like a 105mm-450mm super-zoom. With the Image stabilization turned on, I can actually hold that baby steady enough to use hand-held.



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This work by Ajoy Muralidhar is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.
text and images © 2008 ajoy muralidhar. all names, websites, brands and technical data referenced are the copyright or trademark of their respective owners. thank you for visiting olympuszuiko.

I found this little camera on eBay a few months ago, and just got around to running a roll through it. It was in generally good condition, even had a tiny 22.5mm UV filter on the Zuiko 28mm f/3.5 lens. The reason I took so long to clean up this camera was the light seals – the Pen EE has a slide-off back cover, not hinged like a traditional camera – so there is a very substantial seal required on the inside of the bottom cover. My curiosity about the camera finally made me give in and get the seals done.

Yoshihisa Maitani designed the Pen EE. Maitani gained fame as the designer of the exquisite Pen F interchangeable lens cameras and the legendary Olympus OM series cameras. The Pen camera dates back to 1959, but the Pen EE is from 1961. Olympus went on to make many more versions of the ‘automatic’ Pen EE cameras all the way into the 1980’s.

There were 2 versions of the first Pen EE, I have the older version with “Olympus” across the front, instead of “Olympus PEN”. The original version also has the leatherette cover instead of the ‘basket weave’ covering of the later model. One more difference – the older Pen EE has a 1/60 second shutter speed while the later basket view Pen EE has 2 shutter speeds – 1/250 for the Auto mode and 1/30 for the Flash setting.

The Pen EE is a Half Frame camera – that means 2 images for each frame of 35mm film. The 35mm format is 24x36mm, so half frame is 24x18mm in vertical format. It’s a small image, but the 28mm Zuiko lens is sharp enough to enable nice quality prints up to 8 x10 inches if used with a tripod, and 5×7 inch prints easily when hand-held. The film ISO range only extends to 200 ASA. The 28mm f/3.5 lens provides great depth of field, so it’s a point and shoot camera.

A fixed 1/60th second shutter speed on my Pen EE. That’s it. It’s the same if you set it on Auto or Flash on the original Pen EE. In the Auto mode, the selenium cell light meter sets the aperture automatically, while if you use the Flash mode, you can set the aperture from f/3.5 to f/22, but still at 1/60 second. That’s tricky.

I wanted to use the Sunny 16 rule with the camera, but the slowest print film available to me is ISO 100. Now the Sunny 16 rules says that for film speed for 100 ISO, the shutter speed will be 1/125 second at f/16 in bright sunny conditions. With the fixed shutter speed of 1/60, I would end up with pictures on the overexposed side by one stop. To compensate I would have to close down the shutter by another stop to f/22 to get an equivalent exposure.

The alternative is to set to f/16 and deal with the overexposure later with digital correction (by increasing shadow). In most cases, this will be fine, since the film has enough latitude to handle some overexposure and still produce a decent image. However, since the best color reproduction usually requires a slight under-exposure, it may still be a little too much.

This also means that to use the Pen EE in manual mode with Sunny f/16, we are limited to 100 speed film or lower. 200 ASA film would overexpose by 2 stops, and while film has a great deal of latitude, that much over-exposure would be difficult to correct. Of course, in shade or in cloudy conditions, the aperture range is more than adequate.

In my case, I tend to overexpose an additional stop in cloudy over cast conditions – instead of closing down the aperture, I was actually opening it up from sheer force of habit because of conditioning with my Ricoh 500G and Olympus OM cameras. Now that I’ve a chance to examine the results, I would say f22 for Sunny conditions, f/16 for slight overcast, and f/11 for shade (f/8 and f/5.6 only if you are really unsure.)

As far as the film development goes, any photo processing lab can handle it since it’s just regular 35mm film processing. My advice is to have them develop and put it on a CD, and make a special note to NOT cut the film into strips. Don’t ask them for prints. Later, you can split the half frame images apart using cropping software. Make one copy of each digital image, and then crop the left side from one copy and the right side from the other copy. You can then save to a CD/Card/flash drive and get it printed like any other digital image. I use Walmart’s one hour service and they do a great job, costs $4.23 and beats sending it a specialty processor out of state.


Pen EE
Pen EE
Pen EE
Pen EE
Pen EE
Pen EE
Pen EE
Pen EE
Pen EE
Pen EE
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Pen EE
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Pen EE

Pen EE
Pen EE
Pen EE
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Pen EE

Photographed with an Olympus Pen EE (28mm f/3.5) on Fuji Super 100 film


Pen EE Camera #168426
Pen EE Camera #168426

Pen EE pictures photographed with a Panasonic Lumix DMC LC-20 2 megapixel digital camera


text and images © 2007 ajoy muralidhar. all names, websites, brands and technical data referenced are the copyright or trademark of their respective owners.
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