Question about "true" macro lens

[Robin Usagani]

At first I was wondering how the blur can look like diamond shaped.. then it hit me that it is probably chain linked fence LOL.

All of those were taken with my Sigma 105mm F/2.8 EX DG macro.

Mark

 

[j-digg]

So far my 100mm Macro 2.8 IS has worked pretty darn well at a distance for portraiture.. I like this one of my future brother in law and his 2 boys:

However, dedicated "portrait" lenses apparently have quicker and more accurate AF in comparisson.

I recently heard/read something about that a 100mm Macro lens is actually equivalent to an 85mm when its being used at a distance, and only achieves 100mm when it is at full magnification ( 1:1 )... can anyone shed some light on that?

 

[Markw]

Im not sure about the exact figures, but it is true that macro lenses are only what they say when they are at 1:1.

Mark

 

[Bryce]

One thing I don't think gets enough credit is macro filters. I have a macro lense and I still preffer my macro filter. I have a +4 that I put on my 50mm 1.8. The filter has no focal distance but does great close up. The filter cost me $11 and I think you can get the whole kit for $15 wich has 4 filters on Amazon.

 

[Markw]

The thing with macro filters is that you lose infinity focus. Also, the DOF is generally ridiculously thin. This was taken with a Quantaray +10 macro filter:

Nikon D90
Nikon 28-80mm F/3.3-5.6G
Quantaray +10 Macro Filter
1/200s
ISO 250
F/8

Mark

 

[Josh66]

I recently heard/read something about that a 100mm Macro lens is actually equivalent to an 85mm when its being used at a distance, and only achieves 100mm when it is at full magnification ( 1:1 )... can anyone shed some light on that?

Maybe more like 95mm... I can tell the difference (easily) between my 100mm macro and my 85. It does zoom in/out a little as it focuses in the macro ranges though. But it's not something that you would notice at non-macro ranges.

It might not be exactly 100mm, but I think it's close enough that it doesn't really matter. The 85 probably isn't exactly 85mm either.

Pretty sure most lens focal lengths are rounded...

 

[Overread]

Im not sure about the exact figures, but it is true that macro lenses are only what they say when they are at 1:1.

Mark

A true macro lens is always a true macro lens - that is a lens capable of acheiving 1:1 magnification
However a macro lens only achieves macro magnification when focused to its closest possible point - it then achieves 1:1 magnification and the photos taken at that point are then considered to be true macro photos.

However remember that if you go beyond 1:1 - eg into 2 or 3:1 you are still taking macro photos. At some point things turn into micro though I've no idea where that boundary lies.
Also remember that many things like flowers, dragonflies and butterflies appear in macro sections and are considered macro shots even though many of the shots are in fact 1:2, half macro, scaled shots.

One thing I don't think gets enough credit is macro filters. I have a macro lense and I still preffer my macro filter. I have a +4 that I put on my 50mm 1.8. The filter has no focal distance but does great close up. The filter cost me $11 and I think you can get the whole kit for $15 wich has 4 filters on Amazon.

I do agree macro filters are great thing, but I far far prefer getting proper high quality diopters (incorrectly called macro filters by many). Highquality options are ones like the canon 500D and 250D as well as the raynox series of macro diopters (eg the Raynox DCR150 and DCT250)

The thing with macro filters is that you lose infinity focus. Also, the DOF is generally ridiculously thin. This was taken with a Quantaray +10 macro filter:

True you lose infinity focus, that is their main downside. However as for depth of field its not a property of the diopter, but more a property of increasing the magnification factor. Far as I know all current DSLR methods of boosting magnification lose you more depth of field the higher you go - if there are differences between diopters, extension tubes and single lens contructs (eg canon MPE65mm macro) they are so small as to have no effect when out in the field.

I recently heard/read something about that a 100mm Macro lens is actually equivalent to an 85mm when its being used at a distance, and only achieves 100mm when it is at full magnification ( 1:1 )... can anyone shed some light on that?

Maybe more like 95mm... I can tell the difference (easily) between my 100mm macro and my 85. It does zoom in/out a little as it focuses in the macro ranges though. But it's not something that you would notice at non-macro ranges.

It might not be exactly 100mm, but I think it's close enough that it doesn't really matter. The 85 probably isn't exactly 85mm either.

Pretty sure most lens focal lengths are rounded...

Far as I understand it almost all current macro lenses will reduce in focal length and aperture as they get into the 1:1 area and its part of how they achieve close focusing distances.
Note that Nikon owners tend to notice the aperture change because their camera bodies report the effective aperture setting of the lens setup - so at 1:1 they are at around f5.6. However Canon camera bodies don't report this change so at 1:1 they are at f2.8.
The reality is in both cases the lens is at the same aperture (f5.6) and the light let through is the same - the only difference is in how the lenses and camera bodies are reporting this to the user - canon sticks to the aperture blades themselves whilst nikon give you the effective new aperture of the lens.

 

[Bryce]

If you use a shorter lense like a 50mm you gain DOF. The larger the number on the filter the less DOF you have. I never use over +4 because the quality just goes away.

The thing with macro filters is that you lose infinity focus. Also, the DOF is generally ridiculously thin. This was taken with a Quantaray +10 macro filter:

Nikon D90
Nikon 28-80mm F/3.3-5.6G
Quantaray +10 Macro Filter
1/200s
ISO 250
F/8

Mark

 

[Bryce]

I don't think this DOF is bad at all. This is my 18-55 lense with the +4 macro filter.

 

[Overread]

I disagree that the quality goes with higher diopter power ratings - again this is most likley a difference with cheap end and high end market options. These are all taken with my 8+ diopter (raynoxDCR250) and I would have no problem adding other higher power diopters to my setup - though at present with the MPE I've no major push to get more diopters for the moment.

http://farm3.static.flickr.com/2566/3902073130_06c29faa3a_o.jpg

http://farm4.static.flickr.com/3644/3320216267_aab8175563_o.jpg

And yes depth of field can be very very tiny - its a challenge then

http://farm4.static.flickr.com/3379/3407470294_68debf4c8a_o.jpg

 

[Bryce]

I like the last 2 but number 1 demonstrates the lack of DOF.

I disagree that the quality goes with higher diopter power ratings - again this is most likley a difference with cheap end and high end market options. These are all taken with my 8+ diopter (raynoxDCR250) and I would have no problem adding other higher power diopters to my setup - though at present with the MPE I've no major push to get more diopters for the moment.

http://farm3.static.flickr.com/2566/3902073130_06c29faa3a_o.jpg

http://farm4.static.flickr.com/3644/3320216267_aab8175563_o.jpg

And yes depth of field can be very very tiny - its a challenge then

http://farm4.static.flickr.com/3379/3407470294_68debf4c8a_o.jpg

 

[Overread]

aye true, but if you want the magnification factor then the depth of field loss is something you have to (sadly) live with. You can however use focus stacking to combine a series of differently focused shots into a single composite photo that will give you increased depth of field whilst still keeping the magnification the same and not losing sharpness (which is what you get if you simply keep making the aperture smaller and smaller- because of diffraction).

eg

 

[err_ok]

I don't know about you guys but my 60mm Micro Nikkor is pretty speedy on the old focusing.. I guess it has less distance to travel than a 105mm though

but newer ones like canon's 100mm L you can limit the MFD when you're using it for other-than-macro shooting

They actually removed that on the newer Nikons rather than adding it


Edit: Hmm did not realise there was a page 2