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35mm Adapter Headaches (LetusXL)


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#1 Alastair Crimshaw

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Posted 01 January 2010 - 06:00 PM

Im struggling to get consistently good shots with my LetusXL. Here is the culprit:

Posted Image

I have the following lenses for it:

Nikkor 50mm F2
Nikkor 35-75mm F3.3 AF
Korean Macro 35mm F2.8

From what I can tell the zoom lens is garbage but the other two seem ok. My problems are with light. On a sunny day when I can stop down both my lens and adapter I get some nice crisp images like the one below.

Posted Image

On not so nice days I get some pretty nasty shots like below. I couldn't even stop down my lens or adapter. Both are at F2.8. (I realise the white balance is off) The image is very soft when both the lens and adapter are wide open.

Posted Image

Would it be worth adding gain to the image in order to be able to stop down the lens and get a sharper image? Im in two minds about the LetusXL. On one hand it is difficult to use unless you have a TON of light. When shots work, they look awesome.

Any tips?
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#2 Adrian Sierkowski

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Posted 01 January 2010 - 08:11 PM

The problem with all adapters is that they'll act as a diffusion filter, softening the image by means of the ground glass. That being said, all lenses perform better a bit off of wide open or all the way closed down, somewhere in the T2.8-5.6 range (T2.8 on some lenses, not all, most will work best 'round 4/5.6) Now, the problem is such that on those adapters you really need to be wide open or else risk seeing the pattern of the ground glass (wide open both on your taking lens and the camera lens), so softer results come about often. Also, note that still lenses aren't designed really for what you're doing.
What can help in the perception of sharpness is contrast, either done in the lighting, or done in post (sacrificing some detail). In post, I preffer to work with curves to help build in some contrast missing in shooting by making a "blacker black." I just did a quick "curves" adjustment in photoshop as well as adding in a warming filter for the blue cast, it helps, a bit, though the real solution is scene contrast and working at a bit of a deeper stop.

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#3 ryan knight

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Posted 02 January 2010 - 01:50 PM

The problem with all adapters is that they'll act as a diffusion filter, softening the image by means of the ground glass. That being said, all lenses perform better a bit off of wide open or all the way closed down, somewhere in the T2.8-5.6 range (T2.8 on some lenses, not all, most will work best 'round 4/5.6) Now, the problem is such that on those adapters you really need to be wide open or else risk seeing the pattern of the ground glass (wide open both on your taking lens and the camera lens), so softer results come about often. Also, note that still lenses aren't designed really for what you're doing.
What can help in the perception of sharpness is contrast, either done in the lighting, or done in post (sacrificing some detail). In post, I preffer to work with curves to help build in some contrast missing in shooting by making a "blacker black." I just did a quick "curves" adjustment in photoshop as well as adding in a warming filter for the blue cast, it helps, a bit, though the real solution is scene contrast and working at a bit of a deeper stop.


even your first image isn't that sharp. i've used an adapter many times (the results always vary) and what i always try to do is get both the SLR prime and the camera's stock lens at it's sharper point. for the XL2, it's probably between 3.4 and 5.6, like it is with the DVX. i think the XL2's lens is a 1.7 at full wide to 2.8 or 3.2 at full telephoto, making it's spot between the 3.4 to 5.6 range. stop your SLRs down by two to two and 2/3s closed from wide open and that'll be their sweet spot.

what i also do is quicken the shutter a touch to 1/60, it'll make images appear sharper as well.

good luck.
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#4 David Rakoczy

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Posted 03 January 2010 - 10:38 AM

Alastair 'C',

Per the rules of this forum, please go to My Controls and change your screen name to your first and last name.

The Members thank you in advance. :)
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#5 Chris Keth

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Posted 03 January 2010 - 12:53 PM

How well is the adapter set up? Is the flange focal depth bang-on for the lenses you're using?
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#6 Christopher Santucci

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Posted 03 January 2010 - 04:03 PM

Just a hunch, but I'm guessing the main issue is with this...:

Korean Macro 35mm F2.8

.
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#7 Alastair Crimshaw

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Posted 03 January 2010 - 06:01 PM

How well is the adapter set up? Is the flange focal depth bang-on for the lenses you're using?


The adapter is set up correctly. The relay lens focus is adjusted correctly to give the sharpest image. The flange focal for the Nikon lenses is also ok since the adapter is designed for Nikons.

Just a hunch, but I'm guessing the main issue is with this...:

Korean Macro 35mm F2.8


The Korean lens isn't actually that bad but obviously isn't as good as the Nikkor 50mm. The Nikon zoom lens is the worst out the lot. The image below was shot with the Korean 35mm and for £5 it isn't overly bad, especially since this is wide open.

Posted Image

I think light is my main problem. Here are two image taken with a Nikkor 50mm. One shot in bright sun and the other in dull light.

Posted Image

Posted Image

My original question still stands. In dull light is it worth putting the gain up to +3 and beyond in order to be able to stop down both the lens and adapter?

Also what is more important to stop down, the Nikon lens or the relay lens?

Thanks.
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#8 Chris Keth

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Posted 03 January 2010 - 09:14 PM

The adapter is set up correctly. The relay lens focus is adjusted correctly to give the sharpest image. The flange focal for the Nikon lenses is also ok since the adapter is designed for Nikons.


That's not really what I asked. Have you ever set the flange focal depth and actually measured it? Just because the adapter is made for nikons doesn't mean that it's set properly within the device. This is the biggest problem with lens adapters, in my experience. Most owners I know don't know enough to set them up properly, rentals rarely come to you properly set up, and once set up properly, they don't hold it very well.

A good test would be to see whether stopping down the front lens helped the sharpness more than stopping down the attached camera lens.
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#9 Mathew Rudenberg

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Posted 03 January 2010 - 09:56 PM

Ahh, the older Letus adapter...

I used that one a little, in my experience the issue was really the lens behind the adapter, ie the one that connects to your camcorder.

I found that I could keep the lens in front at pretty much any aperture I wanted to get the depth of field I desired, however the rear lens was much pickier. Anything below a 4 resulted in a significant loss of sharpness, and below a 2.8 all the highlights began to bloom as well, much like your picture demonstrates.

You listed the lenses you put on the front of your adapter, but what is the lens at the back? Shooting wide open with an extreme close focus will tax any lens... is it a macro lens? does it have a diopter on it to focus that close? what quality is the diopter?

Any chain is only as strong as its weakest link.
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