Need dSLR lens tutorial

[GoBlue!]

OK, I'm totally buying into the statement that as I shop for a first dSLR, I'm really shopping for a family of lenses that will be with me for eternity.

First, need #1 for my dSLR is going to be shooting topside pics, mainly child/portraits, at first. Need #2 will come down the road, and that will be u/w pics.

Now, I'm a newbie when it comes to understanding the ins & outs of SLR lenses. I understand the 1.5/1.6x magnification issue when taking a film lens & placing it on a digital camera due to the smaller imager. I understand that low focal lengths (below 50mm film equiv) are wide-angle & higher are telephoto. I understand f-stops when it comes to depth of field issues, and realize that they relate in some way to focal length (getting on shaky ground here).

A few things I'm wondering:
(1) What are advantages to the fixed-focal length lenses compared to zoom lenses?
(2) Is there a glossary anywhere of all the abbreviations that are strung together in many of the lens "names"? (ED, IF, AF-S, letters immediately after f-stops, etc.)? Very confusing.
(3) Without starting an all-out war, as I realize that Canon & Nikon both make excellent high-end lenses, is there anything I should be considering between these two when making an initial purchase?
(4) Could someone please explain "fast lens" and "slow lens" and how they relate to other parameters?

Thanks. I appreciate your patience in advance!

Jim

 

[ssra30]

Welcome to the alphabet soup of SLR/dSLR lenses
I am by no mean an expert on these but as I know
1) prime lenses generally have better optics, less moving part etc. 60mm macro lens has always been considered one the sharpest lens that Nikon make. However many zoom lenses have excellent optics while some are rather poor.

2) Those referred to certain features that the lenses have, type of focusing mechanism and extra feature such as vibration reduction etc. Each brand has its own alphabet soup of letters so may be you want to check the manufacturer's site of each lenses for the specific.

3) I prefer Nikon, not because I believe that Nikon glass is better but for underwater use, Nikon has a couple of good lenses that Canon does not yet offer. Specifically the 10.5mm and 70-180mm macro. When I decided on Nikon, Canon also did not have the equavalent of the 12-24mm lens but that has already been remedied.

4) Fast lens has bigger aparture (smaller F-stop) so you can shoot at higher speed.

Well, I hope that's accurate

 

[fdog]

Jim, welcome to the money pit of new DSLR equipment. I'm a Nikon shooter, and not that familiar with Canon except that it is good stuff, so I'll confine my comments to something I really have first hand knowledge about.

As a quick forward, I'd point out that (using film as an example) that all the shooters I've worked with consider a 35mm lens to be a "normal" lens, not the 50mm, which actually is generally considered a short telephoto. The only 50-ish lenses I've ever owned have been the 55mm Micro and the 58mm Noct, both specialty lenses.

Since you mentioned portraits, the classic lens for this is 85mm (again refering to film). The perspective of the human face seems to be the best with this lens. For general, head-to-toe and in-close type shots I'd use a 28mm. For the uses you've articulated, a good film lens would be a 24-85mm zoom. Digital, the 18-70mm zoom that is part of the D70 "kit" is actually quite good, and covers the perspectives you need handily.

So, on to your questions:

Speed: I'll get this one first, since it helps with the others. Speed refers to the lowest numerical f-stop of the lens. Faster lenses are brighter and easier to focus through the viewfinder. They permit photos in less light. They cost more, too.

Zoom vs Prime: Generally, "Prime" lenses (fixed focal length) have advantages in speed, quality, and size/weight. For equivalent focal lengths, primes are faster by about 2 stops, although you can get speed in a zoom if you bring a wheelbarrow of cash. Modern zooms are much sharper than they traditionally have been, many so sharp that the difference between them and primes is only something a professional would notice. However, zooms still (even the best) have a problem with ghosts and flare, which are unwanted light in the image. Primes, much less so.

Expect to pay twice as much for equivalent primes to cover a particular zoom lens' range.

Zooms are undeniabally handy...you don't have to be changing lenses all the time. I believe, however, that for someone who wants to seriously learn quality photography, zooms are a liability at first, in that they reinforce bad habits.

Abbreviations: try this link .

Canon vs Nikon: Ummm...can I pass? Honestly, the performance differences between these two brands (at the DSLR end) is miniscule. You will be happy either way, believe me. If there is some feature that appeals to you, or a better price, then pick that direction and jump. You really can't go wrong either way. There are differences, just not things worthy of evangelical flame wars. They're just tools. Sheesh.

Since it's early in the morning and I'm bored, I included a chart of my relative lens use at film focal lengths. Terrestrial use, of course. You'll have to apply the applicable conversion factor for whichever DSLR you're considering.

All the best, James

 

[ChrisA]

).
A few things I'm wondering:
(1) What are advantages to the fixed-focal length lenses compared to zoom lenses?
(2) Is there a glossary anywhere of all the abbreviations that are strung together in many of the lens "names"? (ED, IF, AF-S, letters immediately after f-stops, etc.)? Very confusing.
(3) Without starting an all-out war, as I realize that Canon & Nikon both make excellent high-end lenses, is there anything I should be considering between these two when making an initial purchase?
(4) Could someone please explain "fast lens" and "slow lens" and how they relate to other parameters?
Jim

#1. fixed focallenght lens can be built with f-stops going to f/1.2 a zoom lens might open up to f/2.8 but most are in the f/4.0 to f/5.6 range.

#2. Ignore those lettrs and read the full specifications. the leters are a shorthand for what you will see if you read the ful spec sheet. It basically tells you what kind of glass is inside, if there is a focus motor in the lens or not and if there is an image stabilizer in the lens and in the case of Nikon what dat is passed from the lens to the camera and how.. Read the spec sheets

4) A lens the opens up to f/1.8 is "fast" and one that opens up tio f/5.6 is "slow.
The reason is that for a given amount of light and a give film/sensor sensitivity to make a "correct" exposure you would use a "fast" shutter speed at f/1.8 and a slower shutter speed at f/5.6 So, "fast" and "slow" refers to the shutter speed you would use at the maximum lens opening.. The term goes back the the1800's when a "fast" lens allowed to to take a picture inonly seconds as oposed to minutes. No days a "slow" shuttr might be 1/15th second and "fast" 1/2000th second.

Going back to question #1. fixed focallenght lenses can be much "faster" allowing you to shoot n lower light or reduce the depth of feild.

You talk about child portraits. My best work in that area is with an 85mm f/1.8 lens and a one foot square "softbox" mounted to a stroboframe bracket.

Canon vs. Nikon. I'm a Nikon owner but I'm likely to sell it all at very little of my Niko equipment can be used with the N70. I'd be starting over so I may as well pick up the Canon 20D and a new EX strobe.

 

[ChrisA]

(3) Without starting an all-out war, as I realize that Canon & Nikon both make excellent high-end lenses, is there anything I should be considering between these two when making an initial purchase?
Jim

One more thing to think about. When you choose a system you are also betting on the future. You may buy a Nikon camera body, a strobe and a few lenses. but in a few years you will want to replace the camera body so you are betting on who will have the better camera body in five years or in ten years. That's hard to predict. Canon always comes out with new bodies more frequently then Nikon. but Nikon is a more conservative company and builds solid products even if they are not on top of the current tecnology. But look at the new Olympus. They have always produced first rate equipment.

Once you start with a system you are commiting to buying products that are not yet even on the drawing boards. Really I guess it is the same with a magizine subscription you are commiting to buy a product you can't see. What you really are doing is gambling some money on the company.

 

[RonFrank]

A few things I'm wondering:
(1) What are advantages to the fixed-focal length lenses compared to zoom lenses?
(2) Is there a glossary anywhere of all the abbreviations that are strung together in many of the lens "names"? (ED, IF, AF-S, letters immediately after f-stops, etc.)? Very confusing.
(3) Without starting an all-out war, as I realize that Canon & Nikon both make excellent high-end lenses, is there anything I should be considering between these two when making an initial purchase?
(4) Could someone please explain "fast lens" and "slow lens" and how they relate to other parameters?

Thanks. I appreciate your patience in advance!

Jim

1) With todays lens technology there are little differences between high end zooms, and fixed focal length lenses when it comes to image quality.

Lenses tend to be weakest when they are pushing limits. So a zoom that has a big range (say 35mm-350mm) is going to be weakest shooting wide open at the 35mm and 350mm end. That said, I would avoid zooms that have a focal lengh covering much beyond 3x. Fixed focal length lenses are generally very good, and often faster than their zoom cousins. You also get what you pay for, so don't assume all Nikon lenses (for example) are great, they are not. You would be better off IMO purchasing the inexpensive Nikon 50mm f1.8 vs. the Nikon 28-200mm 3.5-5.6 G lens if quality is a primary concern. However the 28-70mm f2.8 Nikon, while slower, is going to produce quality similar to the 50mm f1.8, but include a much more useful range of focal lengths.

2) Most manufacture websites have a glossery to explain the terms they use. Most terms while unique to a manufacture have similar meaning across manufactures. Nikon uses a Term like ED (Extra low dispersion glass), and Tamron uses SD (super low Dispersion glass). You can then start to compare apples to apples when comparing different manufactures.

3) Canon stinks, so go with Nikon Choosing a camera system is a very subjective task. Nikon and Canon rule the 35mm style DSLR world right now, but there are other manufactures like Sigma, Fuji, Minolta, Oly that make good DSLR's. Nikon is the only manufacture that I'm aware of that has used the same F mount lens mount across both AF and MF camera's. This means that one can actually attach some fairly old and interesting MF lenses to the new Nikon bodies. IMO right now the choice should likely be between Canon and Nikon as they provide a huge assortment of glass and both have third party manufactures making glass for them as well. Fuji makes cameras that use the Nikon Mount, as does Kodak.

4) Fast lenses have larger max apertures. This makes a big difference in a LOT of area's that many don't consider. One is that the view finder in an f2.8 lens is TWICE as bright as the viewfinder in an f4 optic. They also allow more light to enter the camera, so they allow the use of lower ISO values (less noise/grain) and/or can be used at higher shutter speeds.

IMO the BEST way to learn more about photography is to take some classes. The general public seems to think that shooting images is something best learned by purchasing expensive equipment, and shooting. Like with anything in life one gets out of it what one puts into it, and understanding aperture, DOF, and most importantly lighting will help you make better images.