Greetings, all
I am looking into buying my first dSLR soon and also looking at whether or not I should buy the camera with a kit lens, or buy the body only and add my own lens. The problem is, I know nothing about lenses and what all the numbers mean on them!
I'm looking at the Sony alpha 65 that has just come out. It comes with a kit lens; here is a copy/paste off the sonystyles.com website:
Lens Type : A-mount 18-55mm zoom lens
Lens Mount Type : Sony A-mount
Aperture (Max.) : f/3.5 - 5.6
Aperture (Min.) : f/22 - 36
Focal Length (35mm equivalent) : APS-C 35mm eqv. 27mm to 82.5mm
Filter Diameter : 55mm
Lens Groups-Elements : 8 elements, 7 groups
Minimum Focus Distance : 0.82ft (0.25m)
Aperture Blade : 7 blades (Circular aperture)
Aspheric Elements : 2
Lens Weight : 7.4 oz (210g)
I read reviews from those who were given the camera to play with, pre-release, and they said the kit lens wasn't as sharp as other lenses they'd seen on the sony alphas (they mentioned the also-new alpha 77 specifically). That's why I'm wondering if I should get my own lens.
My questions are: What does the "F" number mean? I gather it has to do with how much light gets to the sensor. If so, what does a higher number mean, and what does a lower number mean?
What does the number in millimeters refer to?
What is aperture minimum and maximum? What is a "good number" for low light, and what is good for brighter light?
I have found (or someone told me) that the Tamron lenses are good; any weigh-in on Tamron? I would LOVE a Zeiss lens. I have a small point and shoot from Sony that has a Zeiss in it and I love it; but I don't think I can afford one anytime soon. =-(
I'm really not a numbers fan; I start feel the blank look coming on and drool starting to form at the corners of my mouth when bombarded with numbers. This is why so many questions! Thanks for comments/suggestions, etc!
Robyn
Oh man! You asked some big questions but they are good ones. Let's see what I can do.
First of all...the kit lenses are *never* as sharp as prime lenses or those with fixed maximum apertures. I always recommend ditching the kit lens, buy just the body, and then buy other lenses later. Sure, they will be more expensive to buy, but the kit lens is basically a starter lens and as you become a better photographer it becomes a very fancy paper weight.
The "F" numbers are called stops and it controls the amount of light that enters the camera. Here is the trick: the smaller the number, the larger the aperture. They are opposite. An aperture of f/2.8 is much, much larger than an f/22. When purchasing a lens, you want to get one with a fixed maximum aperture, usually at least an f/2.8.
The number in millimeters refers to focal length, which determines the field of view of a lens, depth of field, and focal reach (or how far out the lens can see). Anything from around 12-20mm is considered wide angle, 20-80 is considered normal, and above 80 is considered telephoto.
The minimum aperture and maximum aperture is what a particular lens is capable of achieving. With kit lenses they are variable, which means as you zoom in and out the maximum and minimum aperture numbers will change. This is bad, especially for low-light conditions. A good low-light aperture is f/2.8 or f/1.8. I believe Canon rules the market right now with an f/1.2 lens, but that is kinda extreme. And expensive.
Here is the low-down on the different brand names of lenses. I've used them all and own quite a few. Tokina makes awesome wide angle lenses. Go with Tamron for normal lenses. And Sigma makes really awesome telephoto lenses.
The F-number, or F-stop, is simply the size of the aperture (the hole the light goes through). A "high number" is actually a small number, because it is a ratio (fraction) - F/22 is a small hole, and F/4 is a large(ish) hole. The smaller the number after the F/ - the larger the hole, and the better for low light (and also for background defocus, or subject isolation). The maximum aperture changes as you zoom with the cheaper lenses (or rather, it doesn't with many of the really expensive ones) - when you zoom in on something, the maximum aperture is automatically reduced. Not a good thing, but unavoidable if you don't have thousands to spend on a zoom lens.
A good F-number is F/4. A great F-number is F/2.8. An awesome F-number is F/1.2
At the other end, well, with a digital camera you don't usually want to shoot much smaller than F/8 to F/11 anyway (it softens the image). But, it does give you more depth of field. Past F/8 or so (for most consumer DSLR cameras) you lose the DOF bonus due to overall image unsharpness. Essentially, that number is not very relevant.
The mm number is the focal length. It is, in essence, how far the light travels inside the lens. The longer the length, the more "zoom" or "reach" the lens has. So, 24mm is quite wide, and 300mm is quite long - the small numbers are good for landscapes, and the big numbers are good for football or car racing. The middle numbers (50mm, 85mm, 100mm etc) are good portrait lengths, and often associated with prime lenses (no zoom function).
Tamron do make good lenses. Zeiss make excellent lenses (though not necessarily worth the expense).
That should be enough to get you started! Good luck.
Here's a link to a really neat and simple "cheat sheet" with photo basics. It illustrates the aperature/f-stop quite well. (If you scroll down, there's a link to download Hi-Res files to your computer - so you can actually read the card.) Just more info for your brain to process. ;-) http://www.pixtus.com/forum/site-info/153508-pixtus-photography-cheat-sheet.html
@jasonbarnette@jinximages@superdex Wow, thanks a lot for the great info! It TOTALLY helps a lot! I have read a lot about cameras and lenses and stuff lately but it's a lot of shop talk and I don't know the terminology. It would be like one of you guys sitting in on a dental meeting and trying to figure out what the heck an MODL on #14 is, and why it may need a PC, or, worse, an FGC with a BU after doing an RCT!!
=-D
The more I read, the more I start the blank look thing.... so thanks for the input! and, @kjarn glad it helped you, too!
I'd send you a jar of peanut butter (prices sure have gone up!) @jasonbarnette if I knew where to send it to. haha!
@2thgirl Oh...and since I explained focal length, aperture, f-stops, and junk...just what IS MODL on #14 and why would it need a PC or, *shocker* even worse, an FGC with a BU after oh damn my head hurts.
@jasonbarnette haha!
#14 is your upper left first molar (first as in "the molar closest to the front of your mouth"). All teeth are separated into five surfaces relative to the center (midline) of the face: Mesial: part of tooth closest to the midline. Distal: farthest away from midline; Buccal: the side of the tooth the cheek rests on. Lingual: side of the tooth the tongue is closest to. Occlusal: part the food is chewed on (the Incisal is the edge of the tooth on a front tooth only that bites through things). So if you have an MODL on #14, that means you have a big cavity that goes from the front of the tooth, over the chewing surface to the back of the tooth and wraps around to the tongue side. A PC is a pulp cap which is a medicine put in after the drilling is done, before the filling goes in, on cavities that are too close to the nerve. The nerve still may die, which would require a root canal (root canal therapy, technically, as all teeth have root canals: it's where the nerve and blood supply live. diseased/dead/dying teeth need root canal therapy to clean the bad gunk out and put in an inorganic material to plug it up) which is abbreviated with RCT. Always after RCTs, you need a crown on the tooth to prevent breakage, as a dead tooth is brittle, like a dead tree branch. FGC is a full gold crown, and a PFM is a porcelain (Fused to Metal) crown. A BU is a buildup: a core that replaces the old filling.
So now next time you go to the dentist, you will know the codes they rattle off to each other when he/she does your exam, which may or may not be a comfort....
=-) @shadesofgrey I haven't had Nutella in a LONG time! I know it's really popular in Italy, and since I WILL be living there in a few years, maybe I should go get some (and pop some in the mail to magically find its way to Jason). =-)
@jasonbarnette@shadesofgrey PS: the size of a dental needle also are categorized in numbered sizes just like the apertures are: the larger the number, the skinnier the needle. a 30 gauge needle is very slim and most comfortable, yet less strong, and a 25 gauge is larger, may be less comfortable, but stronger. a 27 gauge is usually used when giving injections for lower teeth because it has to go in farther and go through more muscle, etc and you really don't want one of those babies breaking off when someone jumps if you get too close to the nerve........ Zoiks! very rare, but possible just the same
@2thgirl If that helps you understand all the more the better (like that sentence makes sense!) You get the idea and that is the important part. I just found out about the goodness that is Nutella. I would be broke if i got to eat it as much as I wanted!
PS, @jasonbarnette, just thinks it magically gets to him in the mail, really it's santa's elves that deliver it, but don't ask him about it, he will deny it! He likes to think he knows what he is talking about!
@jasonbarnette@jinximages You two should write a book together! I've been taking pictures for about year and understand what the numbers on the lens mean, but your explanations go deeper than just that with some very useful advice. The first thing I am going to do is ditch my kit lens and go shopping! Thanks guys!
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First of all...the kit lenses are *never* as sharp as prime lenses or those with fixed maximum apertures. I always recommend ditching the kit lens, buy just the body, and then buy other lenses later. Sure, they will be more expensive to buy, but the kit lens is basically a starter lens and as you become a better photographer it becomes a very fancy paper weight.
The "F" numbers are called stops and it controls the amount of light that enters the camera. Here is the trick: the smaller the number, the larger the aperture. They are opposite. An aperture of f/2.8 is much, much larger than an f/22. When purchasing a lens, you want to get one with a fixed maximum aperture, usually at least an f/2.8.
The number in millimeters refers to focal length, which determines the field of view of a lens, depth of field, and focal reach (or how far out the lens can see). Anything from around 12-20mm is considered wide angle, 20-80 is considered normal, and above 80 is considered telephoto.
The minimum aperture and maximum aperture is what a particular lens is capable of achieving. With kit lenses they are variable, which means as you zoom in and out the maximum and minimum aperture numbers will change. This is bad, especially for low-light conditions. A good low-light aperture is f/2.8 or f/1.8. I believe Canon rules the market right now with an f/1.2 lens, but that is kinda extreme. And expensive.
Here is the low-down on the different brand names of lenses. I've used them all and own quite a few. Tokina makes awesome wide angle lenses. Go with Tamron for normal lenses. And Sigma makes really awesome telephoto lenses.
Does this answer all your questions?
A good F-number is F/4. A great F-number is F/2.8. An awesome F-number is F/1.2
At the other end, well, with a digital camera you don't usually want to shoot much smaller than F/8 to F/11 anyway (it softens the image). But, it does give you more depth of field. Past F/8 or so (for most consumer DSLR cameras) you lose the DOF bonus due to overall image unsharpness. Essentially, that number is not very relevant.
The mm number is the focal length. It is, in essence, how far the light travels inside the lens. The longer the length, the more "zoom" or "reach" the lens has. So, 24mm is quite wide, and 300mm is quite long - the small numbers are good for landscapes, and the big numbers are good for football or car racing. The middle numbers (50mm, 85mm, 100mm etc) are good portrait lengths, and often associated with prime lenses (no zoom function).
Tamron do make good lenses. Zeiss make excellent lenses (though not necessarily worth the expense).
That should be enough to get you started! Good luck.
@kjarn I really need to start charging you for all this. I'm thinking jars of peanut butter will do.
http://www.pixtus.com/forum/site-info/153508-pixtus-photography-cheat-sheet.html
=-D
The more I read, the more I start the blank look thing.... so thanks for the input! and, @kjarn glad it helped you, too!
I'd send you a jar of peanut butter (prices sure have gone up!) @jasonbarnette if I knew where to send it to. haha!
#14 is your upper left first molar (first as in "the molar closest to the front of your mouth"). All teeth are separated into five surfaces relative to the center (midline) of the face: Mesial: part of tooth closest to the midline. Distal: farthest away from midline; Buccal: the side of the tooth the cheek rests on. Lingual: side of the tooth the tongue is closest to. Occlusal: part the food is chewed on (the Incisal is the edge of the tooth on a front tooth only that bites through things). So if you have an MODL on #14, that means you have a big cavity that goes from the front of the tooth, over the chewing surface to the back of the tooth and wraps around to the tongue side. A PC is a pulp cap which is a medicine put in after the drilling is done, before the filling goes in, on cavities that are too close to the nerve. The nerve still may die, which would require a root canal (root canal therapy, technically, as all teeth have root canals: it's where the nerve and blood supply live. diseased/dead/dying teeth need root canal therapy to clean the bad gunk out and put in an inorganic material to plug it up) which is abbreviated with RCT. Always after RCTs, you need a crown on the tooth to prevent breakage, as a dead tooth is brittle, like a dead tree branch. FGC is a full gold crown, and a PFM is a porcelain (Fused to Metal) crown. A BU is a buildup: a core that replaces the old filling.
So now next time you go to the dentist, you will know the codes they rattle off to each other when he/she does your exam, which may or may not be a comfort....
=-)
@shadesofgrey I haven't had Nutella in a LONG time! I know it's really popular in Italy, and since I WILL be living there in a few years, maybe I should go get some (and pop some in the mail to magically find its way to Jason). =-)
@shadesofgrey thanks for paying my way for me, I hope @jasonbarnette accepts this in lieu of peanut butter.
PS, @jasonbarnette, just thinks it magically gets to him in the mail, really it's santa's elves that deliver it, but don't ask him about it, he will deny it! He likes to think he knows what he is talking about!
@kjarn I do what I can! :)
Nutella is awesome though.
@2thgirl Nah...anytime I got to a dentist I pop a couple sleeping pills and usually sleep through most of it haha.
When you posted that photo of Nutella, my face looked like this: