ext tubes, closeup filters, convertors

[hyun]

i read some threads, not sure if i got this right.

using a teleconvertor, will your minimum focusing distance worsen?

doing macro, comparing closeup filter (e.g. canon 500D) with extension tube(s), will closeup filters (especially cheaper ones) cause more distortion, whereas extension tubes don't?

canon 500D sounds good but is there a cheap and reasonably nice alternative brand?

it's easier to use extension on shorter-focal-length lenses like 50 or 80mm because the enlargement is more obvious, whereas a long one like 70-200, at 200 you need lots of extension for the same enlargement?

judging exposure values with extension tubes - just use the camera's TTL meter as per normal, no special calculations necessary?

thanks ..

 

[Sgt. Pepper]

i read some threads, not sure if i got this right.

using a teleconvertor, will your minimum focusing distance worsen?
TC will not affect your min focusing distance, it will remain the same. Thus, increasing your magnification a bit as it increases your focal length.

doing macro, comparing closeup filter (e.g. canon 500D) with extension tube(s), will closeup filters (especially cheaper ones) cause more distortion, whereas extension tubes don't?
Just don’t stack-up too many closeup filters and I guess you’ll be safe from distortion. When it comes to Chromatic Aberration, close-up filters handle this better than extension tubes.

canon 500D sounds good but is there a cheap and reasonably nice alternative brand?
You may try Nikon double elements closeup filter (6T/4T), about 40-50% cheaper than Canon counterpart, performance wise it’s on par.

it's easier to use extension on shorter-focal-length lenses like 50 or 80mm because the enlargement is more obvious, whereas a long one like 70-200, at 200 you need lots of extension for the same enlargement?
John Shaw’s advice is to use it on your longest focal length. And I can confirm that it’s true after using it with my 70-200mm and 100-400mm.
But, if you need to increase the magnification, then use it on your shorter focal length. I’ve tried using 1.4X and 25mm ext tube with 50mm f/1.8, the magnification increased into almost a life-size but the working distance and bokeh wasn’t very ideal.

judging exposure values with extension tubes - just use the camera's TTL meter as per normal, no special calculations necessary?
Yes. Your cam TTL metering can be able to detect the presence of ext tube and adjust the exposure accordingly.

thanks

Hope it helps.

 

[hyun]

Thank you for your excellent reply!

I think I tried a cheap closeup filter before, just 1, no stack. I could detect distortion towards the periphery (full frame film), but that one probably costs like $40 or so only.

Do you find the chromatic aberration in ext tubes obvious?

You may try Nikon double elements closeup filter (6T/4T), about 40-50% cheaper than Canon counterpart, performance wise it’s on par.
And the next cheaper brand below Nikon?

John Shaw’s advice is to use it on your longest focal length.
You mean use ext tube with long focal to achieve macro is most useful...

But, if you need to increase the magnification, then use it on your shorter focal length. I’ve tried using 1.4X and 25mm ext tube with 50mm f/1.8, the magnification increased into almost a life-size but the working distance and bokeh wasn’t very ideal.
So a 25mm ext tube is one of the most useful lengths to buy ..? Is 25 the longest around that most people buy?
The bokeh wasn't ideal because 50/1.8 has intrinsically poorer bokeh anyway, which was magnified, yes?
"Working distance" ... u mean the minimum focusing distance was still too far away?

Thanks!

 

[Sgt. Pepper]

Hi Hyun,

I think I tried a cheap closeup filter before, just 1, no stack. I could detect distortion towards the periphery (full frame film), but that one probably costs like $40 or so only.
What lens are you using? Have you tried using it at full zoom?

Do you find the chromatic aberration in ext tubes obvious?
With 25mm ext tube, I don’t notice any CA.. but adding another 25mm (50mm ext tube) then it’s slightly evident.

You may try Nikon double elements closeup filter (6T/4T), about 40-50% cheaper than Canon counterpart, performance wise it’s on par.
And the next cheaper brand below Nikon?
I guess HOYA.

John Shaw’s advice is to use it on your longest focal length.
You mean use ext tube with long focal to achieve macro is most useful...
When its comes to working distance and bokeh, yes it is.

But, if you need to increase the magnification, then use it on your shorter focal length. I’ve tried using 1.4X and 25mm ext tube with 50mm f/1.8, the magnification increased into almost a life-size but the working distance and bokeh wasn’t very ideal.
So a 25mm ext tube is one of the most useful lengths to buy ..? Is 25 the longest around that most people buy?
To me, if you'll going to own just 1 pc of ext tube, then 25mm is the most ideal. (Not too long, not too short). Kenko offers 36mm, that comes in a set of 12mm, 20mm and 36mm.

The bokeh wasn't ideal because 50/1.8 has intrinsically poorer bokeh anyway, which was magnified, yes?
No. 50mm f/1.8 can have a very good bokeh at open aperture. There are lot's of factors to get a good bokeh that's not pertaining to the lens.
Note that you must step-down to f8 and above for macro. The bad bokeh is basically due to shorter focal length that tends to have “more” background coverage.
"Working distance" ... u mean the minimum focusing distance was still too far away?
Working distance is the lens-to-subject distance, not necessarily Min focusing distance.

Thanks!

 

[yahoosg]

May I know what are the factors to consider when buying close up filter? Also, what are the diff between nikon T6/T4? Thx u

 

[Sgt. Pepper]

May I know what are the factors to consider when buying close up filter? Also, what are the diff between nikon T6/T4? Thx u

see whether this helps:
http://www.imaginatorium.org/stuff/cufilter.htm
http://www.central-camera.com/nikon/nikon_accessories/close_up/accessories_for_nikon_closeup.htm

 

[hyun]

I think I tried a cheap closeup filter before, just 1, no stack. I could detect distortion towards the periphery (full frame film), but that one probably costs like $40 or so only.
What lens are you using? Have you tried using it at full zoom?

it was a 50/1.8 with a normal (probably hoya or something inexpensive) regular power (+4? not sure) close-up. maybe close-ups have this "apparent" feel of distortion (i'm just not used to it yet), but on the photo, it looked quite ok. so maybe it was just the feeling of looking thru a viewfinder with close-up attached.

Re: ext tube brands
since they're all just hollow tubes, we're paying for the build of the tube on expensive models..ya? So at which price level or brand for a 25mm does it give value for money? kenko set? original canon? cheap stuff?

Thanks!

 

[Sgt. Pepper]

Objectively, the 25mm Uniplus that costs below 100$ should do the work.

 

[hyun]

so btw the 3 items: ext tube, closeup filter, telecon, the cheapest one item which can expand the photographic range of existing equipment is the extension tube... sounds good!