updated with pictures, post 7...what do these numbers mean?????

[jann1033]

i have an oldish( 6 yrs or so) 100-300 mm lens that says it's macro but has no macro switch like my other sigma macro 28- 80...it says tele-macro(1:4) so that's is the macro ratio( think)...then the infinity sign -1.5m(4.92 ft) so if that what the macro focuses to?from infinity to 4.92 ft???? then the 100-300mm1:5-6.3 @ 55mm know tht 100mm stuff, the 1:5-6.3 i thought was the f stop but maybe not since i don't know what the 1 would be and the @55 would mean one end of the f is at 55mm?( not sure which end but guessing it is the 5 since my 3.5 is at 28 on the other one but since the lens is 100-300 that makes no sense to me what so ever.( who have guessed)

and while i'm asking dumb questions...the manual focus ring has a bunch of numbers in 2 rows, the top is the ft from the 4.92 -50 the bottom1.5- infinity m, which of course you can only control if you manual focus...would that mean the macro only works in mf? it is weird but maybe cause of the f stop it never works( A.focuses ) in anything close to lowish light

NOw.....
on the sigma on the same ring as the macro switch is something that for lack of a better term looks like a volcano with numbers along the bottom 22/10/8 line 8/10/22 when you use the macro at 80mm the 80 lines up with the line in the center but what do the 22, 10 and 8 mean? also along the right of the volcanoy thing are the numbers 80 50 28 top to bottom which must be mm but what is the purpose of the volcanoy thing and the listed mm? don't think it's just for decoration and have been wondering for ages but can't find it anyplace ( probably cause everyone else knows it from birth)so i gotta swallow my pride and ask

since i don't know i will do the appropriate penance which as usually is look really stupid but maybe somebody else wonders also( i hope i hope)

thanks

 

[Kelly Grannell]

I'm confused with everything you posted there but 1:4, to me at least, I don't see that as Macro. I only consider a true Macro lens if it is 1:2 or 1:1.

Cheers,
K

 

[jenny2]

LOL, I'm confused too. Can you post a picture of the lens you're talking about? I lost you with all the numbers

 

[jann1033]

i'l post a picture when my other lens comes today

 

[ndelaware]

i'l post a picture when my other lens comes today

Which lens did you decide on jann?

 

[jann1033]

the one coming today is the 50mm f1.8,( so excited to see how it works!) i just won a kit lens on ebay( got that for wide below the 28 although the pictures of the 18 mm end i saw don't look great i can always sell it if i don't like it. hadn't even bid on it, got my canon rebate back in the mail went on line just to check things out and it was 2 mins to go...i got it for $65 which i thought seemed ok/ about for what they have been selling for (i think ) on ebay...although horse trader in me wanted it for $50or less) and tomorrow if everything goes according to plan i 'm ordering the 28-135 IS ( all canons)

 

[ndelaware]

Congratulations on getting a new lens and a possible second. Here ia a good review of the 18-55 kit lens that discusses the weak and strong points of the lens and how to get better results with it. http://www.photo.net/equipment/canon/efs18-55/

Here is a link at Pbase.com for pictures all taken with the 18-55 lens. Some great pictures there. http://www.pbase.com/cameras/canon/ef_s_1855_35

 

[jann1033]

first lens, the one that says it's macro but no switch

second lens, sigma with the macro switch 28-89

couldn't find my maginfying glass and read the volcanoish numbers wrong the first time( )

 

[Kelly Grannell]

1st lens specification 100mm to 300mm focal length, 1:4 macro capability with the minimum focus distance of 1.5m. The aperture for this lens if f/5 to f6.3

2nd lens, 28mm to 80mm focal length, 1:2 (max) macro capability, manual focus on macro mode, only at 80mm focal length. Don't know about the volcanoey thing.

 

[jann1033]

1st lens specification 100mm to 300mm focal length, 1:4 macro capability with the minimum focus distance of 1.5m. The aperture for this lens if f/5 to f6.3

2nd lens, 28mm to 80mm focal length, 1:2 (max) macro capability, manual focus on macro mode, only at 80mm focal length. Don't know about the volcanoey thing.

thanks ( and don't feel quite so dumb now that the volcanoey thing must be something odd) now for the 1st no macro switch lens...how would the macro ( faux macro) take affect> in that you can focus( well i can;t always on af) at 1.5 m at the 100mm focal length? or does that 55 mean something

 

[Kelly Grannell]

the 55 is the thread diameter of the lens.

A good macro lens can be used as macro lens at any focal length (take for example Sgima 17-70 Macro), the effective minimal focus distance is about 5", depending on the subject and lighting sometimes it can go as close as 2"

 

[Kelly Grannell]

oh, and there is no actual need for macro switch. In ye olde days, yes. Nowadays, not anymore

 

[PaulD]

The volcanoey thing is there to indicate depth of field. I haven't seen those much on the newer lenses. What it tells you is what your depth of field is from your focal point at a particular f/stop. So, if you were focused at 0.5m (at 28mm focal length) then you have acceptable focus from about 0.4m to 0.7m at f/22. If you are at 80mm then (following the lines) you would have acceptable focus from just barely above and below 0.5m.

You can use this graph to figure out what f/stop to use to get your subjects in focus from front to back (and also to figure out your hyper-focal distance).

 

[jann1033]

thanks