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.



Creative Commons License
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.

When I was looking through the Blog Stats for Olympuszuiko, I realized that this is the 100th post. Although I’ve been photographing for  many years, it’s only been a year (almost) since I started WRITING about my experiences with photography and with Olympus and other manual cameras. 

My wife has been telling me for a while to purchase a digital SLR and be done with the expense of film development etc, since I can use my beloved Zuiko, Kiron, Minolta and Vivitar lenses on most digital SLRs with the proper adapter. My T-mount lenses can easily adapt as well. Besides, it would also keep me from continuing to buy bits and pieces of equipment – lenses, bodies and other camera paraphernalia.

While that is true, I would definitely miss the feel of my beautiful manual cameras. My Olympus OM-1, OM1n, OM2, OM2n, OM-10 and OM-PC AND my Minolta Dynax 800si, the Ricoh CR-5, the Yashica TL-Super and the heavy Fujicarex II. Besides, if I gave up film completely, what would I do with the fixed lens cameras – in particular the Olympus Trip 35 cameras, the Ricoh 500G and Olympus 35 RC and Yashica Electro GSN rangefinders? To say nothing of the Pen EE half frame. They would end up on a shelf and slowly rot.

Still, progress cannot be denied. I have been looking into purchasing a Digital SLR for a while, and while it would seem natural for me to purchase an Olympus DSLR – perhaps the E-410 or E-510, but I’m not comfortable with the manual Zuiko compatibility issues, since even with the E-series Four-Thirds to OM Zuiko lens adapter, I will not be able to use the manual Zuikos stopped down to f/11 or f/16 which I use for most of daytime photographs. On top of that, my Minolta AF lenses would languish.

A better option for me is the Sony Alpha series cameras either the Alpha 100 or the new Alpha 700, with their full compatibility with all Minolta AF lenses, including my 3rd party Phoenix, Tamron and Sigma AF lenses. I use them quite a lot, especially the Phoenix 28-105mm and I would definitely be lost if I could not use them on any digital camera I ended up buying. I could use all my Zuiko and other Olympus Mount lenses on the Sony Alpha with the Bower adapter. I’ve used the Bower Minolta Maxxum-OM adapter successfuly on my Dynax 800si and have been pleased with the results.

I’m curious about the Sony Alpha 700, when I have a chance to actually try it out, perhaps I’ll be able to make up my mind. I have heard that Sony has fixed the “noise” issues that were a problem at 400 ASA and above and that the camera is much more rugged. I like the “rugged” part. Can’t ask for the digitals to be comparable with my manual cameras, but I’d sure like something that I could take on a hike without being afraid that it’d would die on me.

I’ve enjoyed writing about my cameras and lenses, and my feeble attempts at photography. As I look over the pictures that I have taken over the past year with a critical eye and compare them with photographs that I have made over the past 9-10 years, I realize that I have made progress in some areas and still need to work on several others – most notably, exposure issues, composition and lens selection.

Oh, well.. like the old saying goes – “the unexamined life is not worth living”. I guess it’s the same for photography. One last word.. I get about 200 hits a day, mostly people who are looking for information about a particular camera or lens. I am grateful to all those who stop by and read my blog… and occasionally leave a comment on a post.

Thank you for stopping by.


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

I finally had the last roll of film from the Baltimore Inner harbor shoot developed this week…. these were with the Minolta Dynax 800si and the Phoenix 28-105mm lens. This is one of my most used Minolta AF lenses, since it spans such a useful range of focal lengths – from wideangle to medium telephoto.

Although it is most useful as a portrait lens, the 105mm is just right for closing in on interesting architectural detail, and the 28, 35 and 50mm focal lengths are always available. I believe that this is the one lens to pack if one is traveling light. I usually carry a Tiffen 812 warming filter in case of overcast or open sky photography and a Tiffen circular polarizer when its bright and sunny out.


Inner Harbor, Baltimore
Inner Harbor, Baltimore
Inner Harbor, Baltimore
Inner Harbor, Baltimore
Inner Harbor, Baltimore
Inner Harbor, Baltimore

Inner Harbor, Baltimore
Inner Harbor, Baltimore
Inner Harbor, Baltimore
Inner Harbor, Baltimore
Inner Harbor, Baltimore
Inner Harbor, Baltimore

Photographed with a Minolta Dynax 800si AF camera and Phoenix 28-105mm f/2.8-3.6 lens on Fujis Superia 200 film. I used a Tiffen circular polarizer


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

Assateague Island is on Maryland’s Eastern shore, on the Atlantic Ocean – just a few miles south of Ocean City, but what a difference. There is none of the hustle and bustle of the hotels and tourist industry, instead, just a peaceful nature preserve, with pristine white sand beaches, very family friendly – and above all, there is peace and quiet.Of course, I didn’t go alone… the whole family was there, and the kids had a great time in spite of the wind and cold water.

One of the unique features of Assateague Island (and believe me, this IS unique – is the population of wild horses. Yes, genuine horses in the wild. Of course, they are correctly termed as “feral” horses, animals that were once domesticated, but which have escaped and bred in the wild over the past few hundred years.

The official record has it that these horses are descendants of domestic animals that Eastern Maryland farmers permitted to graze on the island. They apparently avoided the mainland taxes on the horses, and saved the expense of fencing them in. After all, where would they go on an Island that is little more than a sand bank?

I like to think that perhaps they were survivors from a shipwreck that made it to shore? Or even more intriguing, perhaps they were the property of pirates and salvagers that made their home on that narrow barrier island. I prefer this explanation for the horses on the island rather than the prosaic one of avoiding taxes. The horses are very handsome beasts – they are skittish of course, and it’s best not to get too close, since they can bite and kick, causing serious injury.

I observed tourists feeding and trying to approach the animals in spite of the many warnings and threats of citations and fines. People just don’t appreciate how dangerous a 2000 lb beast can be. Still, the horses frequent the grassy verge by the roads and can be spotted all over. The herd on the Maryland side of the island is estimated at about 300 beasts. The Virginia end is also a National Seashore preserve, with approximately the same number of animals.

The whole place has a magical quality to it… the clean beaches, the wildness of the Atlantic in Spring, when the water is still very cold, the horses, the twisted trees and shrubs that are hardy enough to survive the rugged conditions, and of course, the calmness of the Bay side of the island, the warm sun – all make for a perfect day trip.

The facilities on the island are primitive, but sufficient. It’s best to pack lots of cold drinks and a substantial picnic lunch. And a couple of folding chairs to lounge in. It’s also very windy in the Spring, so a windcheater type jacket is a good idea. I tried to fly my big box kite, but the wind was so strong that the line almost sliced my fingers.

I had taken my Minolta with a Phoenix 28-105mm and a Tamron 70-300mm lens, and an Olympus OM-2n with a Kiron 28-210mm super zoom – the famous cult classic lens. I had also lugged along my Spiratone 400mm f/6.3 preset lens, but did not get an occasion to use it. I had taken the zooms and the long telephoto in case I could not get near enough to get good pictures of the wild horses, but the horses were right by the roadside.


Wild Horses
Wild Horses
Wild Horses
Wild Horses
Wild Horses
Wild Horses
Wild Horses
Wild Horses

Photographed with a Minolta Dynax 800si, Tamron 70-300mm lens, Fuji Superia 400 film, Circular polarizer 1/350 sec at f/13

Wild Horses
Wild Horses
Wild Horses
Wild Horses

Photographed with a Olympus OM-2n, Kiron 28-210mm lens, Fuji Super HQ 200 film, Circular polarizer 1/125 sec at f/11


The Beach has to be seen to be believed. In late Spring, it’s still cold and windy, so there aren’t many people around. Lots of surf fishermen though, trying for Bluefin and Sea Bass. That changes around Memorial Day and then the beach is packed all through Summer until Fall. I prefer the peace and quiet of the off-season, so our next trip will probably be late September or early October.

Dunes
Dunes
Surf Fishing
South Beach
North Beach

Photographed with a Olympus OM-2n, Kiron 28-210mm lens, Fuji Super HQ 200 film, Circular polarizer 1/125 sec at f/11

North Beach
North Beach
Bay Side, near Verrazano Bridge
Bay side, near Verrazano bridge

Photographed with a Minolta Dynax 800si, Tamron 70-300mm lens, Fuji Superia 400 film, Circular polarizer 1/350 sec at f/13



Creative Commons License
olympus/zuiko by Ajoy Muralidhar is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.
text and images © 2007 ajoy muralidhar. all names, websites, brands and technical data referenced are the copyright or trademark of their respective owners. thank you for visiting olympus/zuiko.