GH2 Cheapo 7mm lens

Matthew P

Matthew P

Well-known member
So I have an Raynox wide angle converter (.5x) lens that was bought for my camcorder. I wanted to try it out on some of the lenses I have for my GH2, so I bought some step down filters.

This is it with the 14-42mm kit lens (at 14mm).

Obviously it's nowhere near the quality of a proper 7mm lens (and some post processing is needed), but I've been pleasantly surprised with how it looks, and I think it will be very useful for certain shots where absolute quality isn't crucial (such as a chase scene etc, where lots of camera movement would hide the softness in the corners).

Also tried it on a Sigma 28mm f1.8, and it works very nicely on that indeed (effectively makes it a 14mm f1.8), due to the focal length being more reasonable.

I can imagine this combination working extremely well with the pancake lenses. Beats messing about with wide c-mount lenses, hehe.
 
Nice, though wouldn't it technically be equiv. to a 14, since the GH2's crop factor nearly doubles the focal length of the lens?
 
In a way you're right; it's equiv. to a 14mm lens on a full frame sensor. But, to avoid confusion, it's always best to not take into account any crop factors when talking about lens focal lengths. That would get very messy and confusing.
 
DevonH said:
Nice, though wouldn't it technically be equiv. to a 14, since the GH2's crop factor nearly doubles the focal length of the lens?
Click to expand...

Nope. There is no need to compare it to full frame here, nobody mentioned or is talking about full frame. I hate the compulsion to compare everything to full frame. We are talking about a certain camera here with a certain sensor size, there is no full frame camera involved anywhere. 14mm is 14mm, 7mm is 7mm.
 
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You can get some useable results from some wide angle adapters, but typically there will always be telltale smearing at the corners and sometimes barrel distortion... cropping it to pseudo-widescreen aspect as you've done is a smart way to deal with the degradation at the extreme corners.

I've had good results from a Canon WD58 0.7x adapter from my old PD150 (on lenses with >58mm threads) and a 16x9 EXII 0.6x from my HVX (on lenses with threads >82mm). Be aware that the multipliers are... well, approximate... on most lenses, the WD58 0.7x looks wider than the 16x9 0.6x, and even a poor-quality Chinese 0.5x. I have no idea what the actual resulting focal length is, only that it's about 0.5-0.7x and a good bit wider than before.

And for review, (14 x 0.5 x 2) = (7 x 2)


I actually haven't noticed any light loss whatsoever from either adapter.
 
nothing said:
Doublers affect stop as well, spreading the same amount of light over twice the area, causing a loss of one full stop. The speed of that combo is approximately f2.5.
Click to expand...

I had wondered about this, and it makes sense. Thanks for the insight.

Edit: Are you sure it's a full stop of light loss? I've just taken two pictures, one with the converter on, and one with it off, and there's virtually no difference in exposure. Take a look...

nowaconvert.jpgwaconvert.JPG

(cropped for the same field of view)
 
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Okay, hehe. I just edited that post with some sample pictures ^ really not sure what's going on if it's supposed to be 2 stops of light loss.

I know you'll ask if the camera was on auto. It wasn't, fully manual (f8, 50th of a sec).
 
I'm thinking wrongly again, confusing wide and tele. Disregard me, I'm making coffee now.

Wide converters pack more light in, not spread it thinner.
 
Tele-extenders (ie, make a 50mm lens 100mm lens) lose light, but wide angle adapters don't necessarily lose much light.
 
Very good and prices have been creeping up. For stills, they need to be high quality else the result is quite poor with nearly all defects present. The higher rep wide adapters are better. For vid, the results are acceptable in view of the cost! Fun result, thanks!
 
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