I have been using two lenses of 15× from different brands, to obtain a 30× magnification , but Still for smaller insects I am unable to capture all the details in macro. Is it possible to achieve 1:1 ration ? What should I do to achieve it ?
For 1:1 macro, your distance from the lens should be the same as your focal length. Which is typically about 5mm or so, requiring a lens with 200 dioptres of strength.
But you probably would be fine if it were not 1:1 macro as such but only 1:cropfactor . It would still require an unusually strong lens. At some point of time, one just has to accept that a phone is not a tool for everything.
In most of the cases you can't archive 1:1 ratio because:
- Size of the phone sensor is ~ 4x6mm and insects are bigger (1:1 mean to project entire object 1:1 on the sensor)
- You need to control aperture and be able to use narrow one to get big depth of field
- When use narrow aperture effect of diffraction decrease details
- You need to use fast shutter speed because insects move fast
And at the end please think about the fact most of lens manufactures sell such lens for 500 to 1000 USD/euro (and this is the price of lens, you also need a camera)
In the digital world it makes more sense to measure how many pixels of sensor correspond to a given physical size (which is easy to measure by shooting a ruler as close as possible):
- On my APS-C camera a "macro" lens with the 1:1 ratio covers a 22mm field of view with 5472 pixels, so this is about 249 pixels/mm.
- On my phone, using the 48Mpix mode, the field of view at closest focus is 80mm but since it spans 8000px this is 100px/mm. With a 2.5x magnification I would get the same as with my DSLR.
This said, pixel density isn't the only thing that matters, lack of distortion and noise are important too.
Using the magnification factor (1:1 or else) is however a good indication of how difficult the picture is. To reach 1:1 on your phone you will have to take in account:
- low light (how good is the camera sensor),
- a very shallow depth of field (can you do manual focus?). You can compensate using "focus stacking" but this requires a focusing rails.
- camera shake (which means a camera stand and a remote control),
- alignment of the add-on lens with the built-in lens