how I can get closer?

crayfish74 · Post by **crayfish74** » Sun Mar 10, 2013 9:49 pm

Hi guys,

how I can get closer to the insect, if i want to use all the time my 4x Nikon?

I must change the tube 135 mm than I use to xxx? what mm I will need?
If i will put a teleconverter 1.4x I will expand the magnification?

If there are not solution i must use 10x nikon?

Thanks guys

Ozelot · Post by **Ozelot** » Mon Mar 11, 2013 12:41 am

Hi crayfish,

If you "later pulls a lens" in the reproduction ratio, be reckoned with resolution loss. I've got my 10 BD plan 15:1, and it was still well off. The rest are empirical values.

Greeting

Michael

rjlittlefield · Post by **rjlittlefield** » Mon Mar 11, 2013 12:44 am

Are you using now a 4X infinity objective in front of a 135 mm tube lens?

If so, then you are now getting 2.7X . This is computed as 4*135/200 = 2.7 . The 200 is because that's what Nikon infinity objectives are designed for.

Using a longer lens will give you more magnification. If you use a 200 mm lens instead of 135, then you will get 4X (computed as 4*200/200 = 4).

Adding a 1.4X teleconverter will multiple every magnification by 1.4. So with the 4X objective and 135 mm lens, you will be getting 3.78X (computed as 4*135/200*1.4 = 3.78 ).

--Rik

crayfish74 · Post by **crayfish74** » Mon Mar 11, 2013 4:13 am

Thanks guys,

Very clear now.

crayfish74 · Post by **crayfish74** » Fri Mar 15, 2013 9:39 am

Hi Rik.,

And in the case than I will use the same Nikon 4X infinity objective in front of a 300 mm tube lens ? what will me the real magnificatión?

4x * 300/200 = 6x ?

Best regard.

rjlittlefield · Post by **rjlittlefield** » Fri Mar 15, 2013 9:41 am

Yes, that is the correct calculation.

--Rik

crayfish74 · Post by **crayfish74** » Fri Mar 15, 2013 10:55 am

cool thank - Rik.

crayfish74 · Post by **crayfish74** » Fri Mar 15, 2013 12:40 pm

Rik,

for these lenses and coupling a nikon plan 4x infinite, what lens should fit better? or have better results? , I mean:

I will have a worse light with the 300 f4 + nikon plan 4x infinite? in spite of 135 mm f2.0 + nikon plan 4x infinite ?

rjlittlefield · Post by **rjlittlefield** » Fri Mar 15, 2013 1:29 pm

Sorry, but it depends on exactly what objective, what tube lens, and what camera you are talking about.

Usually vignetting would be worse with the 135 f/2. In exchange, it covers more than twice a field on the subject.

--Rik

crayfish74 · Post by **crayfish74** » Sun Jun 30, 2013 10:07 am

Rik.-

If I want to use the nikon infinite BE 10x 0.25 with a canon 300 mm L, I will have 15x, but:

to use more than 200 mm, the image quality will deteriorate ?

Best,

ChrisR · Post by **ChrisR** » Sun Jun 30, 2013 12:15 pm

With 300mm and a 10x NA 0.25, your effective aperture will be
Magnification/(2 * NA)
=f/30, which takes you well into diffraction territory.

You may find it better to use a 200mm "tube" lens and crop the image. But you may not. It's worth a try!.
Some time ago I tried a 70-300L zoom, Here:
http://photomacrography.net/forum/viewt ... 2328#92328

That zoom seemed to work better at 300 than 200mm.