Sigma Lens Question, which one...18-50 / 24-70

I'm looking for a good replacement for my 400D Kit lens. I would like
something with a similar focal length and $400-600.

I've found these two from Sigma that seem to fit the bill:

18-50mm F2.8 EX DC MACRO
http://www.sigmaphoto.com/images/Len.../150_small.jpg

24-70mm F2.8 EX DG MACRO
http://www.sigmaphoto.com/images/Len...e/63_small.jpg

I just have a couple questions...

Small Sensor
The 18-50MM lens above is "designed for small sensor SLRs" as they say
in the description...

If I get a 5D in the future, which is a full sized sensor, will I be
able to use this lens?

The lens says it's a 18-50, is that what it is if it were on a full
sized sensor camera or is it actually 18-50? (The 24-70 would be like
34-85 on a rebel but 24-70 on a 5D...just estimating)


Age
The 24-70 lens is a few years old where the 18-50 is new, is that a
big deal? (Newer technology = better focus, sharper image, etc...?)


82mm vs. 72mm Diamater
Besides the price of filters going up substansially, am I going to
gain more light by having a 10mm larger opening on the lens? Seems
logical to me but maybe it's such a small detail that it's not worth
worrying about.

Please let me know of your thoughts on these two lenses, and if you
have any answers to my questions, thanks!

"CDZ" wrote in message
ups.com...
I'm looking for a good replacement for my 400D Kit lens. I would like
something with a similar focal length and $400-600.

I've found these two from Sigma that seem to fit the bill:

18-50mm F2.8 EX DC MACRO
http://www.sigmaphoto.com/images/Len.../150_small.jpg

24-70mm F2.8 EX DG MACRO
http://www.sigmaphoto.com/images/Len...e/63_small.jpg

I just have a couple questions...

Small Sensor
The 18-50MM lens above is "designed for small sensor SLRs" as they say
in the description...

If I get a 5D in the future, which is a full sized sensor, will I be
able to use this lens?

The lens says it's a 18-50, is that what it is if it were on a full
sized sensor camera or is it actually 18-50? (The 24-70 would be like
34-85 on a rebel but 24-70 on a 5D...just estimating)


Age
The 24-70 lens is a few years old where the 18-50 is new, is that a
big deal? (Newer technology = better focus, sharper image, etc...?)


82mm vs. 72mm Diamater
Besides the price of filters going up substansially, am I going to
gain more light by having a 10mm larger opening on the lens? Seems
logical to me but maybe it's such a small detail that it's not worth
worrying about.

Please let me know of your thoughts on these two lenses, and if you
have any answers to my questions, thanks!

Hi.

I don't know anything about Sigma lenses, BUT.

An 18 -50 lens is an 18 -50 lens irrespective of any Camera, or none, to
which it is attached.

What you see through the VF and the Image recorded will vary depending on
what size of sensor the Camera has.

Hence the so called "Crop Factor" for Rebels being 1.6., which means that
the lens will provide the same View on a Rebel, as a 29 - 80 would on a Full
Frame sensor.

However the 18 - 50 lens is still, and always will be, an 18 -50.

If it designed for a small sensor Camera, then it will cause severe
vignetting on a Full Frame Camera. You would see a circular image in the
centre of the frame, surrounded by black.

The actual size of the front element, does not indicate more light gathering
ability. That depends on the complete lens construction, and is given as an
"f " number. All f 4 lenses will transmit the same amount of light,
irrespective of their front element sizes.

Roy G

On Jul 30, 8:01 am, "Roy G" wrote:
"CDZ" wrote in message

ups.com...



I'm looking for a good replacement for my 400D Kit lens. I would like
something with a similar focal length and $400-600.

I've found these two from Sigma that seem to fit the bill:

18-50mm F2.8 EX DC MACRO
http://www.sigmaphoto.com/images/Len.../150_small.jpg

24-70mm F2.8 EX DG MACRO
http://www.sigmaphoto.com/images/Len...e/63_small.jpg

I just have a couple questions...

Small Sensor
The 18-50MM lens above is "designed for small sensor SLRs" as they say
in the description...

If I get a 5D in the future, which is a full sized sensor, will I be
able to use this lens?

The lens says it's a 18-50, is that what it is if it were on a full
sized sensor camera or is it actually 18-50? (The 24-70 would be like
34-85 on a rebel but 24-70 on a 5D...just estimating)

Age
The 24-70 lens is a few years old where the 18-50 is new, is that a
big deal? (Newer technology = better focus, sharper image, etc...?)

82mm vs. 72mm Diamater
Besides the price of filters going up substansially, am I going to
gain more light by having a 10mm larger opening on the lens? Seems
logical to me but maybe it's such a small detail that it's not worth
worrying about.

Please let me know of your thoughts on these two lenses, and if you
have any answers to my questions, thanks!

Hi.

I don't know anything about Sigma lenses, BUT.

An 18 -50 lens is an 18 -50 lens irrespective of any Camera, or none, to
which it is attached.

What you see through the VF and the Image recorded will vary depending on
what size of sensor the Camera has.

Hence the so called "Crop Factor" for Rebels being 1.6., which means that
the lens will provide the same View on a Rebel, as a 29 - 80 would on a Full
Frame sensor.

However the 18 - 50 lens is still, and always will be, an 18 -50.

If it designed for a small sensor Camera, then it will cause severe
vignetting on a Full Frame Camera. You would see a circular image in the
centre of the frame, surrounded by black.

The actual size of the front element, does not indicate more light gathering
ability. That depends on the complete lens construction, and is given as an
"f " number. All f 4 lenses will transmit the same amount of light,
irrespective of their front element sizes.

Roy G



Hello Roy,

Thank you for your response, I just wanted to clarify my lens diamater
question. If I was to buy two 2.8 lenses, it seems to me the one that
is 10mm larger would let more light actually into the lens, just like
larger diamater binoculars let you see when it's just slightly darker
out. I understand that the apature will only let the camera "see" as
much as the apatature will open but wouldn't you want as big of
opening on the end of your lens as possible?

Maybe that's a bad example...

CDZ wrote:
I'm looking for a good replacement for my 400D Kit lens. I would like
something with a similar focal length and $400-600.

I've found these two from Sigma that seem to fit the bill:

18-50mm F2.8 EX DC MACRO
http://www.sigmaphoto.com/images/Len.../150_small.jpg

24-70mm F2.8 EX DG MACRO
http://www.sigmaphoto.com/images/Len...e/63_small.jpg

I just have a couple questions...

Small Sensor
The 18-50MM lens above is "designed for small sensor SLRs" as they say
in the description...

If I get a 5D in the future, which is a full sized sensor, will I be
able to use this lens?

You will get serious Shading (aka Vignetting) because the lens is not
designed to fully cover the full-format.

The lens says it's a 18-50, is that what it is if it were on a full
sized sensor camera or is it actually 18-50? (The 24-70 would be like
34-85 on a rebel but 24-70 on a 5D...just estimating)

The focal lenght does not change with the camera. The lens is always a
18-50, no matter which camera it is mounted on.
However the viewing angle (that is your perception of wide angle versus
tele) changes with the size of the sensor. And because of the crop factor on
a Rebel (1.6?) this lens will capture on a Rebel only an area which
corresponds to what a 28-80 lens would capture on a full frame camera.

82mm vs. 72mm Diamater
Besides the price of filters going up substansially, am I going to
gain more light by having a 10mm larger opening on the lens? Seems
logical to me but maybe it's such a small detail that it's not worth
worrying about.

Which on has the smaller opening? I bet it's the one that is designed for
the crop sensor. After all that lens only needs to project a smaller
picture.
Both are F/2.8, so the useful light is the same.

jue

"CDZ" wrote in message
ups.com...
I'm looking for a good replacement for my 400D Kit lens. I would like
something with a similar focal length and $400-600.

I've found these two from Sigma that seem to fit the bill:

18-50mm F2.8 EX DC MACRO
http://www.sigmaphoto.com/images/Len.../150_small.jpg

24-70mm F2.8 EX DG MACRO
http://www.sigmaphoto.com/images/Len...e/63_small.jpg

I just have a couple questions...

Small Sensor
The 18-50MM lens above is "designed for small sensor SLRs" as they say
in the description...

If I get a 5D in the future, which is a full sized sensor, will I be
able to use this lens?

The lens says it's a 18-50, is that what it is if it were on a full
sized sensor camera or is it actually 18-50? (The 24-70 would be like
34-85 on a rebel but 24-70 on a 5D...just estimating)


Age
The 24-70 lens is a few years old where the 18-50 is new, is that a
big deal? (Newer technology = better focus, sharper image, etc...?)


82mm vs. 72mm Diamater
Besides the price of filters going up substansially, am I going to
gain more light by having a 10mm larger opening on the lens? Seems
logical to me but maybe it's such a small detail that it's not worth
worrying about.

Please let me know of your thoughts on these two lenses, and if you
have any answers to my questions, thanks!


I'm a Sigma DSLR user and I have the 24-70mm EX DG lens. It is my most used
lens, sharpness is very good. I know a few fellow Sigma users who use the
18-50mm EX and they all have nothing but great comments about the lens. It
will not work with the 5D as others have noted. If you see yourself moving
up to full-frame, the 24-70mm EX lens is the choice.

On Jul 30, 9:28 am, "Peter A. Stavrakoglou"
wrote:
"CDZ" wrote in message

ups.com...



I'm looking for a good replacement for my 400D Kit lens. I would like
something with a similar focal length and $400-600.

I've found these two from Sigma that seem to fit the bill:

18-50mm F2.8 EX DC MACRO
http://www.sigmaphoto.com/images/Len.../150_small.jpg

24-70mm F2.8 EX DG MACRO
http://www.sigmaphoto.com/images/Len...e/63_small.jpg

I just have a couple questions...

Small Sensor
The 18-50MM lens above is "designed for small sensor SLRs" as they say
in the description...

If I get a 5D in the future, which is a full sized sensor, will I be
able to use this lens?

The lens says it's a 18-50, is that what it is if it were on a full
sized sensor camera or is it actually 18-50? (The 24-70 would be like
34-85 on a rebel but 24-70 on a 5D...just estimating)

Age
The 24-70 lens is a few years old where the 18-50 is new, is that a
big deal? (Newer technology = better focus, sharper image, etc...?)

82mm vs. 72mm Diamater
Besides the price of filters going up substansially, am I going to
gain more light by having a 10mm larger opening on the lens? Seems
logical to me but maybe it's such a small detail that it's not worth
worrying about.

Please let me know of your thoughts on these two lenses, and if you
have any answers to my questions, thanks!

I'm a Sigma DSLR user and I have the 24-70mm EX DG lens. It is my most used
lens, sharpness is very good. I know a few fellow Sigma users who use the
18-50mm EX and they all have nothing but great comments about the lens. It
will not work with the 5D as others have noted. If you see yourself moving
up to full-frame, the 24-70mm EX lens is the choice.



Thank you Peter,

I've been reading a lot of reviews over the past few days, they do
seem mixed but mostly really good, always complaining about the loud
focus but I'm sure it's better than my Canon 75-300 IS and canon kit
lens.

I bought my camera & accessories from B&H, would you recommend buying
the 24-70mm EX DG from another retailer? It's 374.95 at
sigmaforless.com but $429 at B&H. I'm a bit nervous about buying
lenses from places I don't know...

Roy G wrote:
[]
The actual size of the front element, does not indicate more light
gathering ability. That depends on the complete lens construction,
and is given as an "f " number. All f 4 lenses will transmit the
same amount of light, irrespective of their front element sizes.

Roy G

Pedantically, no. All "T/4" lenses transmit the same amount of light. F/4
is simply a geometric measurement, and ignores the lens transmission.
See: t-stop he

http://en.wikipedia.org/wiki/F-number

http://modelmayhem.com/p.php?thread_id=168826&page=2

David

"CDZ" wrote in message
oups.com...
On Jul 30, 9:28 am, "Peter A. Stavrakoglou"
wrote:
"CDZ" wrote in message

ups.com...



I'm looking for a good replacement for my 400D Kit lens. I would like
something with a similar focal length and $400-600.

I've found these two from Sigma that seem to fit the bill:

18-50mm F2.8 EX DC MACRO
http://www.sigmaphoto.com/images/Len.../150_small.jpg

24-70mm F2.8 EX DG MACRO
http://www.sigmaphoto.com/images/Len...e/63_small.jpg

I just have a couple questions...

Small Sensor
The 18-50MM lens above is "designed for small sensor SLRs" as they say
in the description...

If I get a 5D in the future, which is a full sized sensor, will I be
able to use this lens?

The lens says it's a 18-50, is that what it is if it were on a full
sized sensor camera or is it actually 18-50? (The 24-70 would be like
34-85 on a rebel but 24-70 on a 5D...just estimating)

Age
The 24-70 lens is a few years old where the 18-50 is new, is that a
big deal? (Newer technology = better focus, sharper image, etc...?)

82mm vs. 72mm Diamater
Besides the price of filters going up substansially, am I going to
gain more light by having a 10mm larger opening on the lens? Seems
logical to me but maybe it's such a small detail that it's not worth
worrying about.

Please let me know of your thoughts on these two lenses, and if you
have any answers to my questions, thanks!

I'm a Sigma DSLR user and I have the 24-70mm EX DG lens. It is my most
used
lens, sharpness is very good. I know a few fellow Sigma users who use
the
18-50mm EX and they all have nothing but great comments about the lens.
It
will not work with the 5D as others have noted. If you see yourself
moving
up to full-frame, the 24-70mm EX lens is the choice.



Thank you Peter,

I've been reading a lot of reviews over the past few days, they do
seem mixed but mostly really good, always complaining about the loud
focus but I'm sure it's better than my Canon 75-300 IS and canon kit
lens.

I bought my camera & accessories from B&H, would you recommend buying
the 24-70mm EX DG from another retailer? It's 374.95 at
sigmaforless.com but $429 at B&H. I'm a bit nervous about buying
lenses from places I don't know...

Sigmaforless is not an authorized Sigma reseller and I got that information
directly from Sigma. The lens they are selling might be grey-market (aka
"import") which won't carry Sigma's full 4-year USA warranty. There's
nothing wrong with grey-market if you want to go that route, B&H sells both
import and USA product. You can't go wrong with B&H, they are the
gold-standard in resllers. I've recently bought from buydig.com. Great
service, no hassle, great price, and free shipping. I don't see the 24-70mm
EX DG listed on their site but other Sigma lenses are in stock so it might
be worth a call to them to see if they can get it for you. I got my lens on
ebay, it might be worth it to check out the offers there. I've bought quite
a bit on ebay and have had great success with all of my purchases.

On Jul 31, 8:00 pm, "Peter A. Stavrakoglou"
wrote:
"CDZ" wrote in message

oups.com...



On Jul 30, 9:28 am, "Peter A. Stavrakoglou"
wrote:
"CDZ" wrote in message

roups.com...

I'm looking for a good replacement for my 400D Kit lens. I would like
something with a similar focal length and $400-600.

I've found these two from Sigma that seem to fit the bill:

18-50mm F2.8 EX DC MACRO
http://www.sigmaphoto.com/images/Len.../150_small.jpg

24-70mm F2.8 EX DG MACRO
http://www.sigmaphoto.com/images/Len...e/63_small.jpg

I just have a couple questions...

Small Sensor
The 18-50MM lens above is "designed for small sensor SLRs" as they say
in the description...

If I get a 5D in the future, which is a full sized sensor, will I be
able to use this lens?

The lens says it's a 18-50, is that what it is if it were on a full
sized sensor camera or is it actually 18-50? (The 24-70 would be like
34-85 on a rebel but 24-70 on a 5D...just estimating)

Age
The 24-70 lens is a few years old where the 18-50 is new, is that a
big deal? (Newer technology = better focus, sharper image, etc...?)

82mm vs. 72mm Diamater
Besides the price of filters going up substansially, am I going to
gain more light by having a 10mm larger opening on the lens? Seems
logical to me but maybe it's such a small detail that it's not worth
worrying about.

Please let me know of your thoughts on these two lenses, and if you
have any answers to my questions, thanks!

I'm a Sigma DSLR user and I have the 24-70mm EX DG lens. It is my most
used
lens, sharpness is very good. I know a few fellow Sigma users who use
the
18-50mm EX and they all have nothing but great comments about the lens.
It
will not work with the 5D as others have noted. If you see yourself
moving
up to full-frame, the 24-70mm EX lens is the choice.

Thank you Peter,

I've been reading a lot of reviews over the past few days, they do
seem mixed but mostly really good, always complaining about the loud
focus but I'm sure it's better than my Canon 75-300 IS and canon kit
lens.

I bought my camera & accessories fromB&H, would you recommend buying
the 24-70mm EX DG from another retailer? It's 374.95 at
sigmaforless.com but $429 atB&H. I'm a bit nervous about buying
lenses from places I don't know...

Sigmaforless is not an authorized Sigma reseller and I got that information
directly from Sigma. The lens they are selling might be grey-market (aka
"import") which won't carry Sigma's full 4-year USA warranty. There's
nothing wrong with grey-market if you want to go that route, B&Hsells both
import and USA product.

We do, but it's worth mentioning that none of our Sigma stuff is "grey
market."

You can't go wrong with B&H, they are the
gold-standard in resllers.

Thank you. Much appreciated!
--
Henry Posner
B&H Photo-Video, Inc.

Thanks for the reply Henry. Please educate me a bit (no sarcasm intended).
My perception is that there is no difference between "grey market" and
"imported". Obviously from your response there is. What exactly is the
difference? BTW, I *finally* got the chance to go to the store. Although I
live on Long Island, I find myself in Manhattan for visits on Saturdays. I
stayed an extra day a month ago so I could go into the store on Sunday.
Wow, I could lose my life savings in that place. It's unbelievable and your
staff and the "system" you use in delivering a purchase is great.

"henryp" wrote in message
oups.com...
On Jul 31, 8:00 pm, "Peter A. Stavrakoglou"
wrote:
"CDZ" wrote in message

oups.com...



On Jul 30, 9:28 am, "Peter A. Stavrakoglou"
wrote:
"CDZ" wrote in message

roups.com...

I'm looking for a good replacement for my 400D Kit lens. I would
like
something with a similar focal length and $400-600.

I've found these two from Sigma that seem to fit the bill:

18-50mm F2.8 EX DC MACRO
http://www.sigmaphoto.com/images/Len.../150_small.jpg

24-70mm F2.8 EX DG MACRO
http://www.sigmaphoto.com/images/Len...e/63_small.jpg

I just have a couple questions...

Small Sensor
The 18-50MM lens above is "designed for small sensor SLRs" as they
say
in the description...

If I get a 5D in the future, which is a full sized sensor, will I be
able to use this lens?

The lens says it's a 18-50, is that what it is if it were on a full
sized sensor camera or is it actually 18-50? (The 24-70 would be
like
34-85 on a rebel but 24-70 on a 5D...just estimating)

Age
The 24-70 lens is a few years old where the 18-50 is new, is that a
big deal? (Newer technology = better focus, sharper image, etc...?)

82mm vs. 72mm Diamater
Besides the price of filters going up substansially, am I going to
gain more light by having a 10mm larger opening on the lens? Seems
logical to me but maybe it's such a small detail that it's not worth
worrying about.

Please let me know of your thoughts on these two lenses, and if you
have any answers to my questions, thanks!

I'm a Sigma DSLR user and I have the 24-70mm EX DG lens. It is my
most
used
lens, sharpness is very good. I know a few fellow Sigma users who use
the
18-50mm EX and they all have nothing but great comments about the
lens.
It
will not work with the 5D as others have noted. If you see yourself
moving
up to full-frame, the 24-70mm EX lens is the choice.

Thank you Peter,

I've been reading a lot of reviews over the past few days, they do
seem mixed but mostly really good, always complaining about the loud
focus but I'm sure it's better than my Canon 75-300 IS and canon kit
lens.

I bought my camera & accessories fromB&H, would you recommend buying
the 24-70mm EX DG from another retailer? It's 374.95 at
sigmaforless.com but $429 atB&H. I'm a bit nervous about buying
lenses from places I don't know...

Sigmaforless is not an authorized Sigma reseller and I got that
information
directly from Sigma. The lens they are selling might be grey-market (aka
"import") which won't carry Sigma's full 4-year USA warranty. There's
nothing wrong with grey-market if you want to go that route, B&Hsells
both
import and USA product.

We do, but it's worth mentioning that none of our Sigma stuff is "grey
market."

You can't go wrong with B&H, they are the
gold-standard in resllers.

Thank you. Much appreciated!
--
Henry Posner
B&H Photo-Video, Inc.