I am having trouble getting my head around the changes in the lenses for DSLR’s compared to 35mm film SLR’s
I new what I was getting when I used an 135mm, 28mm, or 300.

What are the equivalent focal lengths for Olympus, Nikon, and Cannon SLR’s for 35 mm film lenses. Is there a simple formula I can use.

e.g 50mm lens for a film camera = 35mm for Nikon and Cannon but 28mm for oly

I am interested for both above ana below the water.
A table or equivalents or a simple formula would be best.

Thanks

Hello Victor!

For a nikon DSLR, a 50mm film lens "feels like" or has the coverage angle of a 1.5x50= 75mm (is always 1.5 for nikon).
For olympus is 2.0x50mm=100mm (so is 2.0 for oly)
For canon you have different model ranging from 1.6x50 to 1.0x50...

Yep, as David stated, all to do with what system you use.

Nikon 1.5
Oly 2.0
Canon 1.0 to 1.6

I knew this was not going to be as simple as I wanted it to be.

So how can I tell what each cannon lens is going to be the equivalent off?
Or to put it another way which 35mm lens is a wide angle and which one is not?

For cannon do I only need to know 1.6 and 1.0 or are some 1.3?

Looks to me like cannon may be shooting themselves in the foot from my point of view.

Canon 5D and DII use 1.0, others use 1.6
To make it easily understood for any camera find out what sensor it has. If it is a full frame (35mm equivalent) use 1. Otherwise you simply have to check what the crop ratio, 1.5, 1.6, 2.0 etc for that particular camera.

To simplify you life think in degrees of field of view, the so called normal lens of the 35mm was a +/- 50mm focal lenght, that gave you a vield of you of 46 degrees, actually close to what the human eye see (one eye , not both a the same time ) anything with larger field of view than +/- 45 degrees should be considered a wide angle, anything narrower fall into the telephoto category.

The situation has been around forever in film:

Her are some "Normal" lenses for different film format I had so far, all off these were circa 45 degrees of field of view for their respective film format.

35mm film = 50mm lens
6cm x 6cm = 75mm
6cm x 9cm = 90mm
4" x 5" = 150mm
8" x 10 " = 300mm

Field of view is always availble from the manufacturer and easy to find on their website and catalog. I recommend you to be familiar with this method, make's thing much easier and faster to figure out.

Cheers



And the Nikon guy said

Canon 5D, 1DS & 1DSMkII = 35mm (24x36mm) Crop factor 1 - ie lenses act in the same way as they would have on film. A 50mm lens acts as a 50mm lens would on 35mm film.
Canon 1D and 1DMkII = Crop factor 1.3 (lenses act as though they are 30% longer in terms of their field of view). A 50mm lens acts as if it were a 65mm lens on 35mm film.
Other Canon = Crop factor 1.6 (lenses act as though they are 60% longer in terms of their field of view). A 50mm lens acts like an 80mm lens on 35mm film.

Nikon digital SLRs all have a crop factor of 1.5. A 50mm lens acts like a 75mm lens on 35mm film.

Some other manufacturers have adopted formats which are not quite as simple as their ratios are not the same as 35mm (3:2) so they have no directly equivalent crop factor, but all are substantially smaller than 35mm so will have a 'crop factor' significantly greater than 1 also.

Victor, it is not nearly as complicated as you are makeing it sound. Which focal length multiplyer you use does not depend on the lens. It is not canon lenses, nikon lenses, or Olympus lenses. For the most part the lenses are just the same as they allways were. A 50mm lens is still a 50mm lens.

It is Canon Sensors, Nikon Sensors, or Olympus sensors that are different. The lens projects an image, bigger sensors see more of the image, smaller sensors see less of it.

This diagram by Rocha explains it very well.


So the correct way to look at it is that a smaller (2, 1.6, 1.5 crop factor) sensors are just cropping the center out of the image that was produced by the lens.

So the question is how much gets cropped away? That depends on how big your sensor is. Nikon sensors crop by a factor that makes it look like they were taken by a lens 1.5 x longer. So a picture shot with a 50mm lens looks like it was shot with a 50x1.5=75mm lens.

Now olympus has a smaller sensor. It has a multiplication of 2x.

Most of Canon's dSLR's have sensors with a crop factor of 1.6. For all practical purposes you can just leave it at that. Yes, they do make other sized sized sensors, they are very expensive and most people who are going to pay that kind of money, are going to know what they are buying.

The $7000 1DsmkII and the $3000 5D which have 35mm sensors. 35mm is the size which all the other digital cameras are compairing themselves to when they say they has a crop factor. So if you are using either of these cameras the whole crop factor problem/confusion is not applicable. Pictures taken with a 50mm lens look like a picture taken with a 50mm lens. There is also the $4000 1DmkII wich has a slightly smaller sensor with crop factor of 1.3.

So the moral of the story is once you deside which camera body you will be using, you only have 1 crop factor to worriy about no matter which brand you go with.

As far as which sensor size is best, it depends on what you value most.

Just as with the larger formats of film, larger digital sensors will be able to capture more detail (im purposely avoiding the word resolution becausee many people associate pixel count with resolution and pixel count is a horrible measure of resolution = of how much detail will be captured) with less noise (grainyness) and will be able to produce images with very thin depth of field (only a small part is in focus).

On the other hand smaller sensors /film are less expensive and easier to use. The cameras are smaller, they require less light ( when you want everything in focus (large depth of field)), and make it easier to fill the frame with a tiny creature.

For me the best solution is to attach the lens to the camera and look through it. And without having to do any calculations you can see exactly the coverage it will produce!

The you go underwater, find a suitable subject and shoot away. It is not as if we can usually predict exactly the size of the grouper/nudibranch etc that we will see, or how close we will get to it.

Alex

Not exactly because viewfinders are not 100% of the image captured...... just picking on you!!!

Depends on your camera.
I really notice the difference shooting on a D80 this week (shows about 95%) and things keep appearing in frame I thought I'd cropped out - compared with my normal pro body which is close enough to 100% that you don't get any surprises.
Many film bodies only showed about 95% too - but then slide mounts cropped about the same amount.
Alex

I agree with Alex, you don't need to know exactly how much in mm each of your lenses will correspond to in a given digital system. And I bet you will get used to the "new focal lengths" a lot faster than you think, we take tons more photos with digitals (no film to waste). Instant feedback is a great plus too, you have the option to immediately review composition and lighting.

Luiz

P.S.: Just in case you are still wondering, check this nice website by Tamron:

http://www.tamroneurope.com/flc.htm

Just select your focal length on the scale below and click in 35mm or digital (digital being Canon or Nikon, the difference between 1.5 and 1.6 crops is very small).

Thanks everyone for the help, I will have more questions soon.

I am sure that a standard sensor size will happen sometime in the near future or maybe one for DSLR’s and one for point and shoot.

Viz’art the field of view technique looks good, all I have to do now is find where this is quoted for that camera and lens combo.
For Cannon this might be a problem if a single lens fits cameras with different sensor sizes.

I am still in the decision making stage. I have not even decided which manufacturer to go for although I can guarantee the budget will not be $5000+ for a body.

For diving I am coming from borrowed / rented Nikonos systems to Oly C-8080 housed to DSLR. I will be moving soon so that diving will become a regular occurrence, not just a vacation experience.

I will be replacing my film SLR’s and lenses with the DSLR’s as well so it needs to perform both tasks and very well.

So many options, but once I have started to buy new lenses then I am stuck with my decision.
I am not going through the cost of replacing my lenses again, she who must be obeyed would find a new use for the nut cracker if I tried that on.
I will upgrade the bodies etc as required.

In the first half of next year the decision will have to be made.

My Nikon setup has done me proud for over 25 years. I do not expect that my DSLR are going to do anything like as well. So yes I am biased towards Nikon’s however the Oly 330 with live view is tempting, and I have been told the autofocus on the cannon is better.

It is a great pity that I cannot test the various options over an extended period but that’s the way of it. I will just have to continue my research.

Or I could just buy a second 8080 for diving and keep the DSLR for topside, or, or, or

Too many options, decisions, decisions, decisions.

Ah, but there were just as many options in the old days....