Optimum Setup Help Needed???????

[dicklaxt]

I have a 28-135mm with and adaptor and have reversed a 50mm 1.8 on to it,along with a 25mmII tube,,,,,,,,,with these components what is the reccommended setting(starting point) to be used on each lens and what is the magnification with these components used?

This could be mounted either way 50 reversed or the 28-135 reversed would this be any different?

That 72 to 52 adaptor was a bear to find, ended up going via E bay and China,,,,,,,,,cheap enough tho ,shipping included $6.80.

Now lets see if it works taking pic's :)

dick

[dicklaxt]

Okay here's the deal,I could not achieve focus at all with the tube in place but was able to get clear focus with tube removed(50 reversed) from the line up on every possible settings on both lens.The working distance varied from 1 1/2 inch when at 28mm to 3/4 inch when at 135mm,pics tomorrow.

Focus point was at the approx center only of the 28-135 when it was reversed and mag was less

dick

[LordV]

Highest mag would be the 50mm reversed onto the 28-135 set at 135 viz 135/50 = 2.7:1
The ext tube would not add much mag to this setup.
With some setups you can end up with the focus point being on the surface of the front element or behind it making focus impossible.
With a reversed lens system it is normal to use the reversed lens wide open and at infinity focus. The main lens is normally at minimum focus.

Brian V.

[dicklaxt]

I'm trying to sort thru this but it appears and I could easily be wrong, but it looks like the reduction of lens diameter of the 28-135 from 72 to 52 has really affected the field of view on the reversed 50.I'll have to play with it some after I wake up. :).


What do you mean when you say,,,,,,,The main lens is normally at minimum focus.

I can't get anything on paper except a partial image in a circle no matter what I do,thats the necked down FOV I spoke of above,,,,,,,,,,,,get really good focus on the partial image,image area may be large enough for a full size honey bee. Whats with this????



dick

[Warl0rd]

I hope you have both lenses set on MF, and you "focus" by moving the whole rig until the subject is sharp

[dicklaxt]

Yep sure do, still no go
dick