Sigma vs Nikon (Page 3): Nah... the labs report lack of sharpness at 600 mm for this lens. To say it is the same at 400 as Nikon or Canon misses the point. This not a 400 mm lens it is...

Mark7829 Loc: Calfornia

Nah... the labs report lack of sharpness at 600 mm for this lens. To say it is the same at 400 as Nikon or Canon misses the point. This not a 400 mm lens it is a 600 and that is why people buy it. It is also at f6.3 necessitating a higher ISO and longer shutter sped than a f/4 in low light. It also limits your ability to add a TC. It is cheaper but that's about it. Go for it but it is no way equivalent to Nikon on Canon. though many like yourself will try to make that argument.

erickter Loc: Dallas,TX

[quote=MT Shooter]Many people get wonderfully sharp images with them at 600mm, many do not. Those that do have properly tuned the lens to the camera, and most have bought the Sigma USB Dock unit that allows for fine tuning the lens at up to 5 different focal lengths, imp[roving sharpness even more. Those who do not take the time to tune the lens will probably never get the sharpness they desire, but thats their own fault. If you choose to not properly tune the lens than you have no grounds to complain about any lack of sharpness with it. At 600mm the DOF is so VERY shallow that proper focus tuning is imperative. And at 400mm F5.6, it is just as sharp as the zooms from Canon and Nikon, and still LESS than half the cost. Its a win-win situation in my book.[/quote]

Ditto for the Tamron 150-600. I am getting sharp results thru the entire range. Virtually Identical to C and N quality (when done properly).
: :thumbup:

juicesqueezer Loc: Okeechobee, Florida

imagemeister wrote:

FYI, Canon's white lenses do perform an important practical function regarding heat absortion - especially for those of us in the lower latitudes !

You are right on with most all of your posts, but the difference in heat retention between white and black is insignificant when it comes to small objects. Case in point; as a MSF motorcycle safety instructor, many students claimed that white was the lessor of two evils with regards to how hot they get. According to all test reports by both helmet manufactures and independent studies, there was no difference in the heat factor. Only when you have a large area, like a tent, roof of home, etc. was there a difference.
Also, keep in mind the white lenses tend to show dirt or grime vs. the black.
Nikon does offer a grayish white lens and they command a higher price for some reason. Maybe cause it looks like you are shooting with a canon????

imagemeister Loc: mid east Florida

juicesqueezer wrote:

You are right on with most all of your posts, but ... (show quote)

When the "small object" is an ultra sensitive optical/electrical instrument it becomes very significant ! I have black lenses and I have white lenses. The black ones get so hot I can barely touch them when I am out for long periods in sunlight and focusing starts acting up ! This is NOT insignificant - and it affects everything in the lens including lubricants.

So now I am getting white (Canon) lens covers for my non-Canon lenses !

boberic Loc: Quiet Corner, Connecticut. Ex long Islander

imagemeister wrote:

FYI, Canon's white lenses do perform an important practical function regarding heat absortion - especially for those of us in the lower latitudes !

why then are many L lenses not white. And i suppose all the other makers lenses are not used in the lower latitudes. For that matter no canon lenses (other than some L lenses) are white. I guess they are only intebded for use in northern latitudes.

Mark7829 Loc: Calfornia

This white lens heat problem is "Wive's tale" Those who promote it and believe it are likely not photographers.

imagemeister Loc: mid east Florida

Mark7829 wrote:

This white lens heat problem is "Wive's tale" Those who promote it and believe it are likely not photographers.

LOL LOL :lol:

imagemeister Loc: mid east Florida

boberic wrote:

why then are many L lenses not white. And i suppose all the other makers lenses are not used in the lower latitudes. For that matter no canon lenses (other than some L lenses) are white. I guess they are only intebded for use in northern latitudes.

Where ever you are, you can think what ever you want .....Me? I am going with white ! ( That includes my Sony system also)

imagemeister Loc: mid east Florida

Mark7829 wrote:

This white lens heat problem is "Wive's tale" Those who promote it and believe it are likely not photographers.

Those who say this are likely Nikon users ! ? ......

Mark7829 Loc: Calfornia

imagemeister wrote:

Those who say this are likely Nikon users ! ? ......

Okay why are not Canon bodies white as well??????? Show me any article by a professional lab indicating that black lenses have heat problems and subsequent performance issues. I would love to read this industry changing article. Produce it or just shut up.

imagemeister Loc: mid east Florida

Mark7829 wrote:

Okay why are not Canon bodies white as well??????? Show me any article by a professional lab indicating that black lenses have heat problems and subsequent performance issues. I would love to read this industry changing article. Produce it or just shut up.

Sensitive aren't we ?

Likely because the smaller surface area and/or less sensitivity....though if I had my way way bodies would be white also ( except circumstances for camouflage).

I really do not care what a professional lab might say - or Canon for that matter. My view is based on the laws of physics and personal experience at my latitude - which is all I need.

I will put it on my "to do" list ....

boberic Loc: Quiet Corner, Connecticut. Ex long Islander

Mark7829 wrote:

Okay why are not Canon bodies white as well??????? Show me any article by a professional lab indicating that black lenses have heat problems and subsequent performance issues. I would love to read this industry changing article. Produce it or just shut up.

Actually some of them are. The white lens thing is pure marketing. BTW putting a white cover on a black lens is a whole hellofa lot less expensive that paying for Canon white L lenses

imagemeister Loc: mid east Florida

boberic wrote:

BTW putting a white cover on a black lens is a whole hellofa lot less expensive that paying for Canon white L lenses

Yes, I agree - and that is what I am doing with my non-Canon lenses.

imagesintime Loc: small town, mid-America

juicesqueezer wrote:

You are right on with most all of your posts, but ... (show quote)

Mark7829 wrote:

This white lens heat problem is "Wive's tale" Those who promote it and believe it are likely not photographers.

The Canon lenses that are white are the lenses that use fluoride elements in their construction. Fluoride crystals are VERY susceptible to heat. Black Canon lenses do not use fluoride in their construction. For years Nikon said the fluoride did not improve a lens. They changed their mind and their grayish white lenses use fluoride elements. Those Nikon lenses are more expensive because of the added costs of the very expensive fluoride crystals.

MT Shooter Loc: Montana

imagesintime wrote:

Black Canon lenses do not use fluoride in their constructions.

Maybe you could inform Canon of this, they claim ALL "L" lenses have at least one flourite (not fluoride) element in them.