minolta A200/close up lens CL49-200

[simon_fletcher]

WHAT IS THE FOCAL RANGE OF THIS LENS ADAPTOR IN MACRO AT 200MM IE 8MM

MINIMUN 50MM MAXIMUM.

[jcuknz]

don't shout! the working range when adding a CU lens depends on the focusing range of the camera. Your camera isn't very good when at wide-angle, 130mm, but reasonable with 500mm at the tele end of the zoom but it is only a x8 zoom.

 

I'm guessing that the adaptor has a 200mm focal length from it's title and this means that you will have to work between 200 from the subject and a bit closer but not very much.

Working at the telephoto end ... the camera focuses to 500mm or 2 dioptres. the adaptor at 200mm is 5 dioptres ... add them together and you get 7 dioptres or 1000/7 = 143mm

Repeating that exercise with 1000/130 = 7.7 dioptre plus 5d = 12.7 or 79mm. But of course working at wide angle with a 28mm lens you take in a heck of a lot of subject width/area

 

So I would guess the working range will be 200>143mm Tele and you get your framing from using the zoom. and 200mm > 79mm at WA.

These figures are basic theory and the practical can vary sumwhat.

 

Any close-up lens is basically tricking the camera into thinking that infinity is at the focal length of itself and the camera's focus ability then enables you to come closer. The more powerful the CU lens the less range you have and you quickly reach a point of little gain for extra dioptre power. Plus damm all depth of field :-)

[peterblaise]

.

 

Ouch!

 

That explanation hurts!

 

How about a simpler explanation?

 

As far as I can tell, all a diopter "close-up" lens does is move infinity focus to the diopter specification.

 

So a +1 diopter lens moves infinity to 1/1 meter = 1,000mm.

 

A +2 diopter lens moves infinity to 1/2 meter = 500mm.

 

A +3 diopter lens moves infinity focus to 1/3 meter = 333mm.

 

... and so on.

 

I have +1, +2, +3, +4, +7 and +10 diopter close-up lenses, so all together, I can move infinity behind my head! Hahahah! Just kidding. Not that I would put them all together, but they would move infinity to 1/(1+2+3+4+7+10) = 1/27 meter = 37mm.

 

What does that mean? It means that if you thought you had an infinite distance between you and infinity, and suddenly you have 1 meter instead, then whatever proportions near-to-far you had before concerning focus distance and depth of field are equally reduced. Infinity, as far as a camera goes, can probably be considered as any distance beyond about 200 feet or about 60 meters. To take 60 meters down to 1 meter is a 1/60th reduction, and that's probably what happens to our depth of field, also - a 1/60th reduction! I hate close up work. I must use my focusing rail, and that's a pain to set up and still depth of field is so limited!

 

Now, IF the Konica Minolta accessory lens (for the entire DiMage 5 7 A series, by the way, NOT just the A200) is really a "matched" (meaning nicely built, probably at last 2 elements in 1 group) +2 diopter, THEN it moves infinity focus to 1/2 meter = 500mm. That's 60 meters (infinity) to 1/2 meter, or 1/120th scale!

 

What does that mean?

 

I don't know, but someone had to retort JC uknz, and that's as abstruse as I could get! ;-)

 

Anyway, you inquired about setting the camera in MACRO mode, and that limits distance focus to 0.6 meter, 23.6 inches anyway, so all the above is when using the diopter lens in non-macro mode, right? That's how a diopter changes FAR focus.

 

= = = = =

 

To what extent does a diopter change CLOSE focusing distance?

 

Let's measure. Specification wise, my KMDA1 Konica Minolta DiMage A1 Instruction Manual claims to close focus thusly:

 

Wide-angle macro close-to-far focus range: 0.3-0.6 meter, 9.8-23.6 inches

 

Telephoto macro close-to-far focus range: 0.25-0.6 meter, 11.8-23.6 inches

 

I just tested mine and got:

 

Wide-angle macro close focus: 0.24 meter, 9.6 inches

 

Telephoto macro close focus: 0.24 meter, 9.6 inches

 

So, now I slap on a trusty +2 diopter lens (NOT the Minolta custom model ... yet) and it permits me to close-focus to ...

 

Wide-angle macro +2 close focus: 0.2 meter, 8 inches

 

- 16% improvement "over" 0.24 meter, 9.6 inches in close focus range

 

Telephoto macro +2 close focus: 0.22 meter, 8.75 inches

 

- 8% improvement "over" 0.24 meter, 9.6 inches in close focus range

 

How about FAR focus in macro mode with +2?

 

Telephoto macro +2 far focus: 0.38 meter, 15 inches

 

The in-camera manual focus measurement is 0.6 meter, 23.6 inches.

 

This implies a reduction in "far" close focus in telephoto mode of 36%

 

Wide-angle macro +2 far focus: ...

 

I could NOT get a "clear" focus indicator in wide-angle macro mode with the +2 diopter attached. The camera uses contrast to asses focus, and appears happy to focus on objects farther away than 200 feet or 60 meters with the +2 diopter attached in wide-angle macro mode. However, the manual focus indicator is also limited to the same measurement of 0.6 meter, 23.6 inches in wide-angle macro mode. If we presume the same ratio of tele-to-wide for our close focus changes, then maybe it's "only" 18% loss of far focus in wide-angle macro with a +2 diopter? I'm guessing.

 

= = = = =

 

So, Simon, the answer to your question "What is the focal range of this lens adaptor/er in macro at 200mm i.e. 8mm [7.2mm] minimum 50[.8]mm maximum?" is:

 

8-16% closer-focus and as much as 18-36% less far focus, by my measurements and calculations. That is:

 

Wide-angle macro close-to-far focus range: 0.3-0.6 meter, 9.8-23.6 inches

 

+2 diopter: 0.2-0.49 meter, 8-19.3 inches

 

Telephoto macro close-to-far focus range: 0.25-0.6 meter, 11.8-23.6 inches

 

+2 diopter: 0.2-0.38 meter, 9-15 inches

 

I don't own the adapter yet, but that would never stop me from speculating, eh? ;-) Why not buy one and tell us how you like it? I think the qualities of the magnified image are probably more important then the close focus "improvement". You tell us!

 

Click!

 

Love and hugs,

 

Peter Blaise peterblaise@yahoo.com http://www.peterblaisephotography.com/

 

= = = = =

 

PS - The KMD57A series is actually a ~6x zoom, not the factory-labeled 7x, nor the 8x you mention, JC. Got one? Measure an object taken with wide-angle and telephoto views and do the math! Hey, I love the camera anyway, but why claim it's a 7x zoom? Probably because the actual physical focal lengths may measure that way, but the angle of view does not reach quite that far! :-(

[gary_berg]

I believe the 49-200 is about a +4 diopter. I recall from the spec sheet (which is now nowhere nearby to be found) that it got to 1.25X on the old Minolta D5 (which a 35-xx instead of 28-xx like the D7).

 

I think you get to the traditional "life size" with the 49-200. It's not really life size when you consider the size of the sensor, but it'll seem like life size when working with the lens.

 

The A1/A2/A200 actually get very close in telephoto macro mode already, by the way.

 

So the 49-200 is better than a Canon 500D, and about the same as a Canon 250D lens. All 3 have much better optics than the typical inexpensive close-up lenses you buy in kits from Hoya and such. This is because there are two pieces of glass in the Minolta/Canon (and Nikon xT) lenses.

[jcuknz]

There is a simple way to check the approximate focal length of any lens. Get it to project an image of the sun, or other far distance onto a surface and measure the distance between the lens and the surface. So long as the object is more than say twenty feet from the lens any error will be quite small.

 

I appreciate that my reasoning may be strange to later writers ... becuase it is based on my own thinking on the subject from sixty years of photography ... but it seems logical to me and is backed up by empiratical experience.

 

4 dioptre at 250mm is pretty close to 200mm which is a 5 dioptre.

 

Frankly the reply is so convoluted it must have been made by an idiot genius in my book, pathetically trying to put down a serious replier. Altogether completely pointless.