Cameras with removable lenses
- Thread starter melev
- Start date
TimsReef
Member
The numbers in mm
The numbers in mm
Marc,
This may help you understand exactly what those numbers are: Focal Length Tutorial
Tim
The numbers in mm
Marc,
This may help you understand exactly what those numbers are: Focal Length Tutorial
Tim
Ok, I'll throw in my two cents.
first off. the size of the sensor on your camera effects just how wide or telephoto your lens is. If you buy a Canon Eos 1Ds, it has a full size sensor, so a normal lens is about 50mm.
if you buy most other DSLR's they have a smaller sensor and so you have a multiplyer factor to determine it's apparent focal length. often 1.6 on many DSLR's.
next some macro lenses have different characteristics including flatness of the depth of field. I have the Canon 180mm macro and it is not as flat as their 50mm macro. flatness being edge to edge. So the 50mm lens does a better job of shooting things that are flat like artwork than the 180 which has a slightly curved depth of field (more related to the exact distance from the lens than the distance of the center of a plane)
You pay a lot of money to get a lower aperture (fstop) because it takes more glass and often a lot of engineering to bend the rays (without causing other problems) from the outer edges of the lens. Remember that the lower the fstop, the smaller your depth of field (area in focus front to back). On macro lenses, depth of field can be very small, especially the closer in you get. At most typical macro shooting distances you will probably want the most depth of field possible. Therefore you will usually be shooting in a higher fstop like f8, f11, or f16. You can save yourself a lot of money buying a slower lens around f4 instead of f2.8 or smaller. If you use flash, it won't be an issue. If money grows on trees in your backyard I would recommend an L series lens if you have a Canon. They pull out all the stops when they make those lenses. Spending money does not cure everything but I believe in the adage that you don't get what you don't pay for. I must say that with all of this said I have 4 L series lenses in my camera bag 16-35, 24-70, 70-200, and the 180 macro. Unless I am shooting something in my aquarium or a really small creature, the 180 stays in the bag. I often leave it at home when I go on any trip where weight will be an issue.
first off. the size of the sensor on your camera effects just how wide or telephoto your lens is. If you buy a Canon Eos 1Ds, it has a full size sensor, so a normal lens is about 50mm.
if you buy most other DSLR's they have a smaller sensor and so you have a multiplyer factor to determine it's apparent focal length. often 1.6 on many DSLR's.
next some macro lenses have different characteristics including flatness of the depth of field. I have the Canon 180mm macro and it is not as flat as their 50mm macro. flatness being edge to edge. So the 50mm lens does a better job of shooting things that are flat like artwork than the 180 which has a slightly curved depth of field (more related to the exact distance from the lens than the distance of the center of a plane)
You pay a lot of money to get a lower aperture (fstop) because it takes more glass and often a lot of engineering to bend the rays (without causing other problems) from the outer edges of the lens. Remember that the lower the fstop, the smaller your depth of field (area in focus front to back). On macro lenses, depth of field can be very small, especially the closer in you get. At most typical macro shooting distances you will probably want the most depth of field possible. Therefore you will usually be shooting in a higher fstop like f8, f11, or f16. You can save yourself a lot of money buying a slower lens around f4 instead of f2.8 or smaller. If you use flash, it won't be an issue. If money grows on trees in your backyard I would recommend an L series lens if you have a Canon. They pull out all the stops when they make those lenses. Spending money does not cure everything but I believe in the adage that you don't get what you don't pay for. I must say that with all of this said I have 4 L series lenses in my camera bag 16-35, 24-70, 70-200, and the 180 macro. Unless I am shooting something in my aquarium or a really small creature, the 180 stays in the bag. I often leave it at home when I go on any trip where weight will be an issue.
Morgandy
New member
I'm SOO glad you asked the questions Marc....I've been shooting forever, had my own darkroom, did some work for money, etc.., BUT, all I ever did was 'wing it'...the numbers just never 'added up' for me with lenses, etc. So this thread is right on. I just got my first digi dslr, after owning 5-6 other digi's over the years, so good timing to hash this out. My old film cameras all I ever got were macro interchangeable lens for.
For my XTi, I bought a Sigma17-70mm so far, and took these shots, as an example,
and these fish action shots:
http://www.quillworker.0catch.com/es.htm, and these,
http://www.quillworker.0catch.com/aquatech.htm,
Are there other lenses that would have done "better/more" for these kind of shots?
Also, I have been testing it out for people shots like this, and so far it seems like a really good all-around lens within the ranges shown here, if not doing extreme macro or telephoto. But, what others would be comparable I guess is the question, and give me just a bit more flexibility with these fish and people shots at these same distances?
thx!!!
For my XTi, I bought a Sigma17-70mm so far, and took these shots, as an example,
and these fish action shots:
http://www.quillworker.0catch.com/es.htm, and these,
http://www.quillworker.0catch.com/aquatech.htm,
Are there other lenses that would have done "better/more" for these kind of shots?
Also, I have been testing it out for people shots like this, and so far it seems like a really good all-around lens within the ranges shown here, if not doing extreme macro or telephoto. But, what others would be comparable I guess is the question, and give me just a bit more flexibility with these fish and people shots at these same distances?
thx!!!
My girlfriend has a nice Sigma 50mm Macro that takes great pictures. I use a Canon 100mm. The big difference between the two is that she has to be closer to her subject. If you taking pictures of a butterfly that might be important if the bug keeps flying away when you get close.
While you stated (way back when) that you get confused over the mm thing, I get confused over the x zoom. What's a 10x zoom? I assume they have a baseline? So a 35-350mm would be a 1-10x zoom?
Mike
While you stated (way back when) that you get confused over the mm thing, I get confused over the x zoom. What's a 10x zoom? I assume they have a baseline? So a 35-350mm would be a 1-10x zoom?
Mike
gregr
New member
I've been out of the country for the last couple weeks- playing catch-up now 
To answer Morgandy's question about what other lenses will do what you need done-- you've got a very decent focal length in the 17-70. It's what you'd call a "walking around" lens, meaning it's good for anything from landscapes (where you want a very wide angle to fit in a lot of scenery... the Grand Canyon for instance) all the way to portraits. Portraits are head and shoulder type compositions, so a focal length of around 85mm is generally called for. With the Digital Rebel you get a 1.6x multiplier so the 17-70 is actually 27-112. The multiplier thing is the result of the lenses being designed for a standard 35mm piece of film and the sensor on the DR is 1.6 times smaller than a piece of 35mm film.
Common walk around lenses are roughly 24-135mm. Anything in that range is great for everyday stuff... those times when you can only bring one lens. I've got the 24-105 and on this last trip I was on it was the only lens I used. Canon makes a 28-135 that would give you more reach but hurt you on the wide end. Beware the lenses that go from super wide to super long- they make a lot of compromises on the optical quality to get that much reach and still at a low price.
I still think the 100mm macro lens is the best for aquarium photography though- and not just super close-ups.
MCary's question about the x factor is just simple math- the x comes from how many times longer the lens is compared to wide. Zoom lenses are defined by the range of their focal length, with the wide number coming before the long [telephoto] number. That 24-105 is 24mm wide on the wide end (again, good for landscapes, groups of people etc) and 105mm long when it's zoomed all the way in (good for portraits and making subjects further away appear bigger in the picture). So... 24 goes into 105 4.375 times so it would be listed as 4x (4.375x to be exact). A 20-200mm zoom lens would be 10x. 70-210 is 3x and so on. It's an annoying description of a lens because it doesn't tell you anything about the focal range. A 10x lens could be 50-500 or 4-40... what good is that?!
I'll go downstairs and check to see if the 2x extender will work with the macro lens...................................... no go- sorry. You can get it to work though by putting a 10mm extension tube in between. Kenko's set comes with a 10mm tube.
The difference between extension tubes and extenders is this-- extenders help make far away subjects fill the picture while extension tubes make close up subjects closer. Extension tubes are merely empty metal tubes (think of them as spacers) that move the rear element of the lens further away from the sensor and that allows the lens to focus on a subject that is closer than it would without the tubes. The Canon 100mm macro lens can focus on something as close as 7" away roughly- if you add extension tubes you'll be able to focus on something only a few inches away-- and that greatly increases the magnification (makes the subject bigger in the picture).
Extenders are short tubes that do have glass in them- they work basically just like magnifiers, increasing the focal length by 2x (Canon also sells a 1.4x). So if you use a 2x extender on a 300mm lens your focal length becomes 600mm.
Remember- the longer the lens the better they are at making subjects far away appear big in the frame. Wildlife photographers use very long lenses (generally 600mm) to make the animals fill the frame- it's a lot better than walking up to a grizzly bear with a wide angle lens because you'd have to get realllllly close
To answer Morgandy's question about what other lenses will do what you need done-- you've got a very decent focal length in the 17-70. It's what you'd call a "walking around" lens, meaning it's good for anything from landscapes (where you want a very wide angle to fit in a lot of scenery... the Grand Canyon for instance) all the way to portraits. Portraits are head and shoulder type compositions, so a focal length of around 85mm is generally called for. With the Digital Rebel you get a 1.6x multiplier so the 17-70 is actually 27-112. The multiplier thing is the result of the lenses being designed for a standard 35mm piece of film and the sensor on the DR is 1.6 times smaller than a piece of 35mm film.
Common walk around lenses are roughly 24-135mm. Anything in that range is great for everyday stuff... those times when you can only bring one lens. I've got the 24-105 and on this last trip I was on it was the only lens I used. Canon makes a 28-135 that would give you more reach but hurt you on the wide end. Beware the lenses that go from super wide to super long- they make a lot of compromises on the optical quality to get that much reach and still at a low price.
I still think the 100mm macro lens is the best for aquarium photography though- and not just super close-ups.
MCary's question about the x factor is just simple math- the x comes from how many times longer the lens is compared to wide. Zoom lenses are defined by the range of their focal length, with the wide number coming before the long [telephoto] number. That 24-105 is 24mm wide on the wide end (again, good for landscapes, groups of people etc) and 105mm long when it's zoomed all the way in (good for portraits and making subjects further away appear bigger in the picture). So... 24 goes into 105 4.375 times so it would be listed as 4x (4.375x to be exact). A 20-200mm zoom lens would be 10x. 70-210 is 3x and so on. It's an annoying description of a lens because it doesn't tell you anything about the focal range. A 10x lens could be 50-500 or 4-40... what good is that?!
I'll go downstairs and check to see if the 2x extender will work with the macro lens...................................... no go- sorry. You can get it to work though by putting a 10mm extension tube in between. Kenko's set comes with a 10mm tube.
The difference between extension tubes and extenders is this-- extenders help make far away subjects fill the picture while extension tubes make close up subjects closer. Extension tubes are merely empty metal tubes (think of them as spacers) that move the rear element of the lens further away from the sensor and that allows the lens to focus on a subject that is closer than it would without the tubes. The Canon 100mm macro lens can focus on something as close as 7" away roughly- if you add extension tubes you'll be able to focus on something only a few inches away-- and that greatly increases the magnification (makes the subject bigger in the picture).
Extenders are short tubes that do have glass in them- they work basically just like magnifiers, increasing the focal length by 2x (Canon also sells a 1.4x). So if you use a 2x extender on a 300mm lens your focal length becomes 600mm.
Remember- the longer the lens the better they are at making subjects far away appear big in the frame. Wildlife photographers use very long lenses (generally 600mm) to make the animals fill the frame- it's a lot better than walking up to a grizzly bear with a wide angle lens because you'd have to get realllllly close
Last edited:
Morgandy
New member
Thanks Greg, good run-down.
How far away are you typically when you do unbelievable shots like this???
or this?
That first one seems like it would be once in a lifetime shot..a little off track, but how long were you in wait for, or, how were you ready when he/she jumped?
I'm sure you've all seen it, but if not, you HAVE to look at Greg's site. It is mesmerizing!!!!
How far away are you typically when you do unbelievable shots like this???
or this?
That first one seems like it would be once in a lifetime shot..a little off track, but how long were you in wait for, or, how were you ready when he/she jumped?
I'm sure you've all seen it, but if not, you HAVE to look at Greg's site. It is mesmerizing!!!!
Similar threads
