Comparing Digital and Film Lenses

[Designer Dale]

As a long time film photographer, I have been doing my best to educate myself on digital before I dump $$$$ on equipment.
When I look down the barrel of a film lens, the glass takes up most of the diameter of the barrel. Lenses on dslr cameras in the Canon Rebel XS and Nikon D60 range spook me because there seems to be a much smaller lens sitting in the center of the big lens. Big Boys like the Nikon 300 have lenses like I am used to seeing in film cameras. What's the difference between the two styles of lenses?

 

[robbieduncan]

The kit lenses on the DLSRs that you are looking at are likely to be EF-S (Canon) or, I think, DX (Nikon) lenses. These produce a smaller image circle that full-frame (or as you think film) lenses. This results in less glass. In addition these are going to be fairly slow lenses, whereas I would image a lot of your film lenses are fast.

The long and the short of it is that most film lenses work on digital bodies. For example all Canon EF lenses work on all Canon digital bodies.

 

[Cliff3]

Lenses intended for use with APS-C (or 4/3) sensor cameras such as those you looked at are generally designed to cover a smaller image circle, so they can be made physically smaller than a lens intended for use with a 35mm-size sensor. Also, the focal lengths also tend to be shorter since the smaller sensor reduces the field of view covered by the lens at a given focal length. The kit lenses supplied with the consumer bodies you looked at are both small and light. They're intended for consumer use and are mostly plastic, which keeps the weight down as well as the cost.

There aren't too many constant aperture zooms out there in this product category, but I can say that my former Nikkor 17-55 f/2.8 DX lens was not much smaller or lighter than the Nikkor 24-70 f/2.8 that I replaced it with. Those are both professional quality lenses though - large, heavy, of robust construction, and expensive.

 

[Designer Dale]

Thanks for the info. Now that I know where to look on the spec sheets, I see that I can't go to a full frame 35 sensor for under 3 grand. How much do I really loose with the smaller sensor? Are we in audiophile territory here? Pay tons more, but the ear/eye can't really tell the difference?
I shoot landscapes and wildlife, as well as what I call "viewfinder art". Rusty gears and such. I class myself as a skilled hobby guy.

 

[Cliff3]

Thanks for the info. Now that I know where to look on the spec sheets, I see that I can't go to a full frame 35 sensor for under 3 grand. How much do I really loose with the smaller sensor? Are we in audiophile territory here? Pay tons more, but the ear/eye can't really tell the difference?
I shoot landscapes and wildlife, as well as what I call "viewfinder art". Rusty gears and such. I class myself as a skilled hobby guy.

Here's an article that discusses that question in a Nikon context: http://www.bythom.com/d3ord300.htm Both sensor formats have their strengths and weaknesses.

 

[SLC Flyfishing]

Thanks for the info. Now that I know where to look on the spec sheets, I see that I can't go to a full frame 35 sensor for under 3 grand. How much do I really loose with the smaller sensor? Are we in audiophile territory here? Pay tons more, but the ear/eye can't really tell the difference?
I shoot landscapes and wildlife, as well as what I call "viewfinder art". Rusty gears and such. I class myself as a skilled hobby guy.

With a 35 mm sensor, your lenses will perform as they did on your film cameras. That is, a 35mm prime will give you the same angle of view that it did on the film camera. Because the sensor of say a D60 is smaller, the image that gets recorded is a crop of the middle part of the image that a 35 mm lens casts against it. There is a crop factor that comes into play as a result; meaning that on a D60 the 35mm prime lens gives a field of view very similar to a 50 mm prime on a 35 mm film camera.

The take home message from all of this is that your wide angle lenses won't be able to give you as wide an angle of view on a smaller sensor body. For Nikons, Canons, Pentax's, Sony's, and any other DSLR with what's known as an APS-C sized sensor (named so because it's got a sensor roughly equivalent to a frame of APS film) you take the focal length and multiply it by 1.5 to get the equivalent focal length. For Olympus and Panasonic DSLR's (using the 4/3 system) you multiply the focal length by 2 to get the equivalent focal length.

It's tricky because some people feel like this makes a lens longer (which would be great if you shot with tele lenses a lot), which is actually untrue. It's just that you're cropping from the center again so the image appears to be captured with a longer lens. But the same result can be optained by cropping from the center of the image as captured with the same lens on a full frame or film camera.

As for advantages between full frame sensors and cropped sensors (APS-C and 4/3) it's mainly a matter of dynamic range and ISO performance. Full frame cameras will generally have a wider dynamic range, and better performance at high ISO. But crop cameras generally hold the advantage in resolution at given focal length. If I shoot a photo of a deer with a 200 mm prime lens on a Nikon D700 and then the same shot with the same lens on the Nikon D300, the D300 will show more detail on the deer as I crop into the image, this all falls back to the D300 having a smaller sensor so it shoots a cropped image (relative to the D700) and all 12 million pixels are in that image, whereas I'll have to crop some of the D700's resolution away to get the same image, and as a result I'll have a photo with less resolution.

I think that as long as you aren't doing anything professional and/or demanding of extremely wide angled lenses you'll be fine with an APS-C body, the high end ones have extremely good Image quality. They're all good, but the high end ones are not terribly far behind the full frame bodies.

Also, bear in mind that if you want to have the option of upgrading to full frame in the future, make sure to avoid digital specific lenses. (Nikon's are called DX, Canons are called EF-S, Pentax's are called DA, not sure about Sony)



SLC

 

[anubis]

Thanks for the info. Now that I know where to look on the spec sheets, I see that I can't go to a full frame 35 sensor for under 3 grand. How much do I really loose with the smaller sensor? Are we in audiophile territory here? Pay tons more, but the ear/eye can't really tell the difference?
I shoot landscapes and wildlife, as well as what I call "viewfinder art". Rusty gears and such. I class myself as a skilled hobby guy.

Generally, only professionals and the most serious of amateurs pony up the cash for a full frame sensor. They are very pricey and require the best lenses ($1000 each minimum) to get good image quality out of them. Additionally, digital camera bodies tend to depreciate in value much more quickly than lenses, so unless you're a busy professional who takes hundreds of thousands of pictures a year, it's probably not worth it. The serious amateur photographer is more likely to spend money on a few high quality lenses (which last for decades and hold their resale value well) and an inexpensive prosumer cropped frame camera (Canon 50D, e.g.) rather than blow their whole budget on a full frame digital camera that will be obsolete in a few years.

But to answer your question: yes, full frame cameras will deliver better image quality (in the form of reduced noise) than cropped frame cameras, but only when paired with high quality lenses (Canon L-series, for instance)

 

[Designer Dale]

Thanks for the link, Cliff. I put it in my PDF file. My target for getting a DSLR is my retirement date in November.

 

[toxic]

Thanks for the info. Now that I know where to look on the spec sheets, I see that I can't go to a full frame 35 sensor for under 3 grand. How much do I really loose with the smaller sensor? Are we in audiophile territory here? Pay tons more, but the ear/eye can't really tell the difference?

are you familiar with medium or large format? the same applies to APS-C (cropped) and full frame (35mm) sensors. the larger recording surface yields less noise (in the case of digital), more detail resolution, less DoF, and demands less of the lens.

on that last part: this means no, you don't need high-end lenses for good images on a 35mm sensor. you just need better ones because the vignetting and corner softness of the lower-end lenses don't get cropped off as they do on a smaller sensor.

something for you to note: if you like fast, wide-angle primes you don't have many choices with an APS-C sensor. with Canon, you have the Sigma 20/1.8 as your only option for less than $1000. dunno how it is for other manufacturers.

 

[Cliff3]

The serious amateur photographer is more likely to spend money on a few high quality lenses (which last for decades and hold their resale value well) and an inexpensive prosumer cropped frame camera (Canon 50D, e.g.) rather than blow their whole budget on a full frame digital camera that will be obsolete in a few years.

You'd be amazed at what the serious amateur might do. However, a balanced reentry into the hobby would probably see someone starting with an APS-C based body along with a two or three good lenses. Once that person has a better feel for their equipment and how it aligns with their goals and the subjects they shoot, their equipment gaps will become evident.

 

[ChrisA]

Thanks for the info. Now that I know where to look on the spec sheets, I see that I can't go to a full frame 35 sensor for under 3 grand. How much do I really loose with the smaller sensor? Are we in audiophile territory here? Pay tons more, but the ear/eye can't really tell the difference?
I shoot landscapes and wildlife, as well as what I call "viewfinder art". Rusty gears and such. I class myself as a skilled hobby guy.

It's not determined by what you shoot but buy what you do with the image. For example do you display them only on an electronic screen such as a computer monitor or a TV set or do you like to make large format "fine art" quality prints.

Do you currently find that you prefer to shoot fine grain ISO 100 (or slower) film because 400 has objectionable grain or does not capture the color you want. If you do then you will need to take a hard look at the sensors how you process the RAW format images

All DSLR sensors are much more sensitive to light than film. But that is only half the story. With today's technology you would need a full frame 24 mega pixel sensor to capture all the detail and tonal range you can get with the better films. You would have to spend some $$ to have a DSLR that is beeter than film. But do you need that? Most people went to DSLRs for convenience and quick turn around times. If you want very large fine art prints shoot a Hasselblad or 4x5 but if you want to be editing shots from the football game on your computer 30 minutes ater the game get a DSLR.

Today, most people don't even make prints, they look at the images on a glass screen. For that you don't need more than 4 mega pixels and a small format sensor. Even the entry level Canon and Nikon DSLRS are overkill for on-screen viewing and 4x6 prints. So like I said which camera body to use depends on how the image is used