Hoya Magnifier Close-up Set

Started Nov 23, 2008 | Discussions thread
MightyMike Forum Pro • Posts: 40,764
Re: Hoya Magnifier Close-up Set

first off they are not 1, 2 and 4x magnifiers, they are 1, 2 and 4 diopter close-up lenses, they are also simple 1 elements non achromatic close-up lenses... similar in quality to a cheap magnifying glass in front of the lens...

to explain Diopters

1 diopter forces and typical camera lens to focus at 1m + - a little bit of leeway (1m from the front of the lens)
2 diopter forces 50cm
4 diopter forces 25cm
10 diopter forces 10cm
20 diopter forces 5cm (like a reversed 50mm lens)

the higher diopter you go the leeway becomes so much smaller that you end up with less them + - 1mm

in terms of magnification, well that all depends on the initial magnification of the lens... take for instance my Sigma 17-70 @ 70mm has a magnification of 1:2.3 or an FOV of 5.4cm when focused at 20cm "from the sensor", if i put a 1 diopter lens on then i have to focus now 1 meter "from the front lens element of the close-up lens" plus the length from the front element of the camera lens to the sensor (approx 16cm) giving me a focus distance of 116cm not 20cm and therefore a magnification of 1:13.34 or an FOV of 31.3cm... certainly not 1x (more like -5.8x on that lens)

4 diopter is actually 1.25x if i recall correctly (1.25x not related to photography but to loupe magnifiers or 1.25x with relation to the human eye)

now you've got a cheap set of diopter lenses to play around with, i do too but i also own the far far better more expensive achromatic diopter lenses like the Raynox 150 (+5.4 diopter) and Raynox 250 (+9 diopter) lenses and i have previously owned the Raynox 5320 (+2 and +3 diopter set) all of which are multi element chromatically corrected (Achromatic doublets or triplets) this means better sharpness and significantly reduced CA or no CA.

Here is a website with a lot more information on the close-up lenses, it reports the Raynox 150 and 250 as +4.8 and +8 diopter but it depends where you measure the diopter from, I measure from the front element they measure from the back element, sometimes there is little difference.

http://freenet-homepage.de/seemolf/achromats.html

I didn't mean to sound harsh just wanted to be educational as there are a lot of mis-representations and mis-understandings in the technical end of this part of photography, if all you care for is the ability to focus closer then you don't necessarily need to know what all the numbers mean, just get a high enough diopter that will allow you to focus closer then the lens you put it on

you can combine the lenses for a higher diopter, lowest diopter closest to the lens higher diopters out front but on you set it will definitely degrade the quality a lot.

on a prime lens these give very little leeway in terms of magnification difference when you rotate the focus ring from infinity to the closest focusing distance, on a zoom you leave the focus ring at 1 end or the other and adjust you magnification by zooming in and out, when dealing with higher diopters the easiest way to use these is to use manual focus, leave the focus ring alone and move the camera back and forth until what you want in focus is in focus... also you have the ability to get magnifications of 1:1 and 2:1 and even higher but you don't get the benefit a dedicated macro lens gives at 1:1. at 1:1 and lets say F8 the dedicated macro lenses is actually giving you a DOF of F16, but if you use a front mounted close-up lens and achieve the same 1:1 and F8 your DOF will still be F8 meaning you need to stop down to F16 to achieve the same DOF of a dedicated macro lens.

i commonly use F22 and F32 at higher Diopters to achieve at least some DOF this means i need a flash and where the on-board flash is ok a dedicated external flash with a decent diffuser like a gary fong lightspere II Cloud diffuser is worlds better.

I'm sure there are aspects of this photography i haven't covered, if they come to me i'll add them
--
Mike from Canada

'I like to think so far outside the box that it would require a telephoto lens just to see the box!' ~ 'My Quote :)'

http://www.airliners.net/search/photo.search?sort_order=views%20DESC&first_this_page=0&page_limit=180&&emailsearch=mighty_mike88%40hotmail.com&thumbnails=

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