Does using a lens adapter lose you a full aperture stop?

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Does using a lens adapter lose you a full aperture stop?

Postposted on Mon Jan 03, 2011 3:55 pm

I am having issues with my camera with noise in low lights. Its because my camera is auto-setting the ISO super high, and I'm using older Zuiko full manual SLR lenses with an adapter on my Olympus E-PL1. I remember reading that using an adapter will cause you to lose a full F-stop, but I wasn't sure if that was really true or not. It seems like it shouldn't because you're merely putting the lens exactly where it would normally be if it were on the body it was designed for, but people smart that myself designed these things, so what do I know?

So is it true? Or do I just need to pony up and buy a faster lens?
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Mon Jan 03, 2011 5:11 pm

Buy a decent bounceable flash.
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Mon Jan 03, 2011 7:29 pm

I don't see how it can lose any light if there's no glass elements in it. I imagine that the camera is getting confused by the lens data (or maybe the lack thereof?) from the adapted lens, doesn't know how wide your aperture is, and is automagically bumping the ISO to compensate. That, however, is merely a guess, being unfamiliar with the Olympus system or old Zuiko lenses.
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Mon Jan 03, 2011 7:44 pm

Teleconverters cause you to lose aperture (one stop for a 1.4x, two for a 2x, etc). A simple adapter should have no effect on that. Hard to help much more without knowing more about the system or lenses, etc.
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Mon Jan 03, 2011 10:17 pm

bimmerlovere39 wrote:Teleconverters cause you to lose aperture (one stop for a 1.4x, two for a 2x, etc). A simple adapter should have no effect on that. Hard to help much more without knowing more about the system or lenses, etc.



Its micro 4/3 but I'm using an OM -> m4/3 adapter with a 28mm f2.8 lens. Crop factor on the sensor is 2, so its a 56mm. This lens works OK, but I have a 75-150mm F4-5.6 and the kit lens is a 14-42mm f3.5-5.6. The kit lens is actually the worst of the low light offenders.
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Mon Jan 03, 2011 11:24 pm

Yeah, I don't see why you'd lose any light with those converters.

You do "lose" two stops of aperture as far as depth of field is concerned - the bigger the sensor, the better the DOF isolation. From a light standpoint, though, I don't see any problems.
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Mon Jan 03, 2011 11:32 pm

Smaller sensor = less total light falling on it. The micro-4/3 sensor gets about half as much light as APS-C which gets about half as much as a full-frame 35mm sensor. One f-stop is equal to one halving of the light gathering capability.

Your adapter isn't hurting you. A 28mm f/2.8 lens is still a 28mm f/2.8 lens. While it might be thrilling to have the larger sensor of the full-frame (or medium format) camera, most of us aren't ready to plunk down $2500 for an EOS 5D Mk. II.
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Tue Jan 04, 2011 8:34 am

I guess I'm going to pick that up. Decent price, works on or off the hotshoe.

http://www.amazon.com/Olympus-FL-36R-El ... HOW980OPA7
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Tue Jan 04, 2011 9:27 am

JustAnEngineer wrote:Smaller sensor = less total light falling on it. The micro-4/3 sensor gets about half as much light as APS-C which gets about half as much as a full-frame 35mm sensor. One f-stop is equal to one halving of the light gathering capability.

Your adapter isn't hurting you. A 28mm f/2.8 lens is still a 28mm f/2.8 lens. While it might be thrilling to have the larger sensor of the full-frame (or medium format) camera, most of us aren't ready to plunk down $2500 for an EOS 5D Mk. II.


While what you say is true, it is confusing. Each sensor site on any-sized sensor will get the same amount of light from the same lens as long as the sensor site (pixel) is the same size. Only the sensor site size matters (A single red, green, or blue pixel). So from that perspective a FF camera set to 28mm f/2.8 will have the same ISO and shutter speed as a u4/3 camera set to 28mm/f2.8. (caveat: as long as ISO100 of FF == ISO100 of u4/3, they are NOT always the same). Only real difference is the CROP of the projected image onto the respective sensor.

DPReveiw will list sensor sizes to help compare, but ISO vs. aperture vs. shutter speed is consistent from camera to camera with the same lens. The same lens on any camera body will always have the same projected image size and brightness. You sensor size simply limits how much of it can be "seen" at once.

A simple tube lens adapter does NOT loose light, but tele-converters do. Basic math on a tele-converter is f-stop = f/(aperture * magnification) so a 1.9x tele-converter would take your f-stop from f/2.8 to f/(2.8 * 1.9) = f/5.3. This may not always be true depending on the tele-converter design, but in general it is a good rule of thumb.
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Tue Jan 04, 2011 10:25 am

The 4/3 sensor is roughly 2/3 the size of the larger APS-C found in most nikons, and approx 70% the size of the APS-C's found in Canons according to this:

http://en.wikipedia.org/wiki/Four_Thirds_system

But yeah, what he's saying is if 2 sensors are different sizes, and both are 10mp, the larger one will have better low light performance because each pixel is bigger. However if a sensor thats 10mm sq is 5mp and one thats 12mmsq is 15mp, the smaller one may actually have better low light performance due to the fact that each pixel itself is larger.
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Tue Jan 04, 2011 5:33 pm

Suggestion: If you don't like the initial results while doing bounce flash, try adding a home-brew card diffuser. Self-adhesive velcro strip and a plastic or laminated card in the 3x5" to 5x7" range does the trick pretty neatly.
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Wed Jan 05, 2011 9:19 am

ludi wrote:Suggestion: If you don't like the initial results while doing bounce flash, try adding a home-brew card diffuser. Self-adhesive velcro strip and a plastic or laminated card in the 3x5" to 5x7" range does the trick pretty neatly.


Another trick is to just use a rubber band around the flash head - that way, you don't have to worry about glue residue and/or need to put a corresponding velcro strip on the card.
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Wed Jan 05, 2011 9:23 am

I posted in the other general thread, btu this is what I ended up with just forcing the ISO and using a tripod:

http://picasaweb.google.com/ian.g.case/ ... 0703050994
Image
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Wed Jan 05, 2011 9:29 am

Ah, you're using an E-PL1.

Just a heads-up, the m43 sensor will have low gain noise in general.

If you take a picture of bright blue sky in the middle of the day and look at the RAW, you can see noise in the sky even at ISO200, it's just how the format works (I have a GF1) and is nothing to worry about.

The shadow noise in your pic seems well controlled.
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Wed Jan 05, 2011 9:33 am

Voldenuit wrote:Ah, you're using an E-PL1.

Just a heads-up, the m43 sensor will have low gain noise in general.

If you take a picture of bright blue sky in the middle of the day and look at the RAW, you can see noise in the sky even at ISO200, it's just how the format works (I have a GF1) and is nothing to worry about.

The shadow noise in your pic seems well controlled.

Yeah, it was just intolerable when it was using ISO1600 on full auto with the kit lens for just snapping pics.

http://picasaweb.google.com/ian.g.case/ ... 0375895266
Granted the lighting wasn't spectacular in the room, but it wasn't terrible either. Theres a fairly bright halogen floor lamp behind me. If you do a 100% crop of that it looks like it was taken with a webcam or cell phone.
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Wed Jan 05, 2011 4:29 pm

Also make sure you have any features the "lift the shadows" turned off.
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Re: Does using a lens adapter lose you a full aperture stop?

Postposted on Fri Jan 07, 2011 12:31 pm

Corrado wrote:http://picasaweb.google.com/ian.g.case/Random#5555831070375895266
Granted the lighting wasn't spectacular in the room, but it wasn't terrible either. Theres a fairly bright halogen floor lamp behind me. If you do a 100% crop of that it looks like it was taken with a webcam or cell phone.

It looks to me like the camera metered to the light on the LCD monitor, which is why the display is completely legible while the rest of the image is dark, and excessively noisy if you try to crank it up. If the camera had metered to the available light on the desk and wall, those would be normal and the LCD would be a washout and probably blooming. You would need to either brighten the room considerably, or dim the LCD, to bring them back in balance.
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