Lens Magnification

[vimwiz]

Macro lens with bellows/tubes/extension rails.

 

[Overread14 2]

Wait what's the 4x you're referring to>?

 

[IronMaskDuval]

 

[480sparky38 37]

If using close-up filters makes it possible to focus further away, then it seems you're using them wrong.

 

[IronMaskDuval]

If using close-up filters makes it possible to focus further away, then it seems you're using them wrong.

Please school me on how to not use them wrong.

 

[IronMaskDuval]

But then again, I might just be stupid. I think it's stupid.

 

[480sparky38 37]

If using close-up filters makes it possible to focus further away, then it seems you're using them wrong.

Please school me on how to not use them wrong.

You typically just screw them on to the front of your lens, just like any other filter.

 

[IronMaskDuval]

You typically just screw them on to the front of your lens, just like any other filter.

Thanks! And all this time, I thought I was supposed to tape it to the LCD. Not srs

 

[Overread14 2]

A close up filter will increase your minimum focusing distance and also your maximum. As a result you should be able to move the lens closer to the subject of choice and thus get an increased magnification; it doesn't mean you "have" to of course so it could be that you're feeling that you were focusing from further away because you were and were not pushing the lens to its limits.

 

[pgriz]

Well, it seems that the 4x didn't do me any favor other than allowing me to focus further away. Not quite what I'm looking for. Am I noobish dreaming?

A 4x diopter allows you to bring the minimum focussing distance closer to the camera, and in doing so, fills up more of the screen with the subject, giving you the magnification. Check what your minimum focusing distance is without the diopter. Then put it on and check it with the diopter. You'll find the minimum focusing distance to be much less in the second situation.

The problem with the add-on lenses, is that they don't usually provide an equally sharp image across the entire width of the frame. Dedicated macro lenses are designed to give you a sharp image across the entire field, and are designed to give you the ability to adjust your focus very precisely at close range. Add-on lenses don't have that ability.

 

[Overread14 2]

The problem with the add-on lenses, is that they don't usually provide an equally sharp image across the entire width of the frame. Dedicated macro lenses are designed to give you a sharp image across the entire field, and are designed to give you the ability to adjust your focus very precisely at close range. Add-on lenses don't have that ability.

It depends greatly on the make and brand. The optical quality of filters can be very advanced - advanced enough that is has a very minimal effect on overall optical quality - an effect that is further masked often in macro when using small (sharper) apertures and also after editing for display.

In tests the Canon MPE 65mm macro (100% pure macro lens) has been beaten by assemblies of diopters and other optics in pure optical quality (though the MPE remains the only viable zoom option).


Fine focusing, which you mention in the last part is certainly only a property of the lenses being used. Though in my experience once you've got the magnification set to contain the frame content you want you leave the focus alone and use back/forward motion to place the final location of the plane of focus.

 

[IronMaskDuval]

So it appears that I was correct. I am stupid. Not having a tripod, I couldn't get the shot that I want. The "window" of focus is so small, that if I move too quickly, it's gone. I managed to pull of a good shot without a tripod. I'm going to pick one up tomorrow and go spider hunting.

 

[Overread14 2]

Keep practising and you'll get there.

 

[480sparky38 37]

So it appears that I was correct. I am stupid. Not having a tripod, I couldn't get the shot that I want. The "window" of focus is so small, that if I move too quickly, it's gone. I managed to pull of a good shot without a tripod. I'm going to pick one up tomorrow and go spider hunting.

Welcome to the Thin World of Macro DOF.

 

[TheFantasticG]

When working with that thin of a DoF you might want to consider getting a set of focus rails. I have a set for such occasions.