Panasonic 7-14 mm

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Hi, Im using Lumix FG2 & Subal case with 2 x S&S YS110 strobes. I have a flat port for 14mm lens (works nicely but produces cromatic aberration at corners), an other flat port for DG 45mm macro (absolutely top lens) and I also have a zoom gear + dome port for the 7-14mm lense.

I selected the 7-14 over fisheye to "try do things differently to the main stream" as nearly all my UW friends shoot wide angel using fisheye. However, Im having serious problems with this lense and before putting more money in my gear & getting the fisheye, I though to see if someone here know more about this lense.

First problem is obvious, corner focus is terrible, I guess the only solution is to keep them in blue and if they are not, use vignetting to darken them with photoshop. More suggestions ?

Secondly, I constantly loose lots of shots as the camera simply refuses to take the picture, funny enough for me it looks like it does focus (I see green focus squares in screen), but stil it takes no picture. Anyone else experiencing this ?

And lastly, and most disappointingly, the minimum focus distance is terrible ! I need to be like a metre (3feets) away from the subject to safely focus. at 14mm its worse than at 7mm. My dome is the subal 4" and not sure if the placement of lens inside is then wrong, the done is too small, or what ? at air I get much much closer minimum focus distance.

I use manual mode only, mostly central focus, sometimes multiarea focus, f/6..f/11 typically. My fear is that buying the 8mm fishey & fitting extension ring, will not fix my focus problems but just gives me different pictures. ANy good advice will be much appreciated. ... and yes, I also hate the fact you need to put the whole dome port in parts to remove the memory card when using 7-14 lens. :) hehehe.

// Cheers, Markku
 
Jack, thanks a lot for all that great info. About the 7-14mm lense, have you noticed it does focus much better at 7mm, but at 14mm the focusing needs more contrast and distance to the subject. e.g. at 7mm you need on metre (3ft) but at 14mm you need at least half the distance more, 1.5m (4..5ft) ?? //Markku
 
PHILRUDIN-AUGMASTR-1.JPG-6150015.jpgPHILRUDIN-AUGMASTR-1.JPG-6150016.jpg


To begin to understand how lenses as wide as the Panasonic 7-14mm work under a dome port you may want to read the attached, Digital Immersions: Pool tests for optimized corner performance on various wide angle lenses underwater

Here a test is being done with the Nikon 14-24mm zoom on a full frame camera with a nine inch GLASS dome port and a number of different extension ports. The 14-24 lens has the same 114 degree angle of view as the Pana 7-14 at the 7mm end of the lens. Among the findings is that an extension port with as little as a 5mm difference in length made a great difference in corner sharpness at 114 degrees. Expecting a one size fits all type of port to work with such a wide lens a bit of a pipe dream. Other lenses are tested as well and the less AOV the better the results. The Tokina 10-17 fisheye is also tested and like all fisheyes the results are better with less equipment.

Look at the ZEN ports, the 9-18/14-42 port has the same port glass as the 7-14 ZEN port but the ports are a different length to get best results. Second the glass has the same curve as a 170mm dome even though the glass is only around 100mm. The six inch Nauticam dome for the 7-14 zoom has a port equal to the curve of about a 230mm dome.

To compare the 7-14 to the 8mm fisheye is like apples to oranges. For best results with a fisheye you need a hemisphere not a curved port and it can be much smaller. The ZEN port for the Pana 8mm is the same glass as used for lenses like the Tokina 10-17 and Nikon 10.5 fisheye on APS-C sensors as well as the Canon 8-15 fisheye. The size of the dome alone allows you to get better CFWA than with the larger six to nine inch dome ports.

The bottom line is that the Panasonic 7-14 zoom can produce stunning results even with soft corners. The corner issue with any rectilinear lens as wide as 114 degrees is going to be the same and regarding your port selection you will likely get the results that you pay for.

The differences between rectilinear and fisheye are huge and I think most U/W photographers tend to tilt towards one or the other as their go to W/A lens.

The attached images give a little bit of an idea of how different the Panasonic 8mm fisheye is v. the Panasonic 7-14mm zoom at 7mm. Images taken 18 inches from the flat subject.

Phil Rudin
 
Jack, thanks a lot for all that great info. About the 7-14mm lense, have you noticed it does focus much better at 7mm, but at 14mm the focusing needs more contrast and distance to the subject. e.g. at 7mm you need on metre (3ft) but at 14mm you need at least half the distance more, 1.5m (4..5ft) ?? //Markku

Markku; I only shot it a few times and don't own the lens. But what you are saying in terms of focusing distance is in line with how close it, or any lens, can focus at a wider or narrower focal length. As far as the AF, it's the same issue, it's not seeing as much subject and you're further away, so it will be darker. Physics is a bi*ch.

Jack
 
This lens will focus at 25cm (10") both at 7&14mm with or without using auto focus. That's 25cm from the sensor not the end of the lens. It will do the same under water with a proper dome port. When I spread my thumb and small finger apart in a V the distance from thumb to finger is about 22cm. If I put my thumb on the dome and the finger to the subject I can gage minimum focus distance within a cm or two. This also works well for a 24 degree macro lens like a 100mm eqv.

If you are having to shoot from 1 to 1.5 meters with the 7-14 you have some type of problem, most likely with the port and extension configuration.

Phil Rudin
 
I agree with Jack. First off, 7mm is silly wide. Strobes will not cover the complete image (you can see that in the above GH-2 images). I have the 10bar gh1 housing, and while I do shoot with the lens, I only use it above 10mm. Sort of a limited zoom.


Stopping down does improve the corners, but you now will end up with dark background, which if that is what you want, then great.

If I am in clear water and come face to face with a whale shark, the 7mm would be nice to have.


I happen to think the Oly lens would be a much better choice, and a much more usable zoom range.

Regarding which case...I have two 10bar cases. They work, just not really well. For example, the stainless steel shafts are only sort of stainless (they rust over time), and the controls mostly work, some not very well. What they are is low cost.

Am a huge fan of Nauticam cases.
 
I have used both the 7-14 and the 9-18 quite a bit. While I think the 9-18 is an excellent lens for the price in no way do I think it is a better choice than the 7-14. First ALL zoom lenses have a small drop in IQ at the widest setting making the 7-14 a better lens at 9mm than the 9-18 at 9mm. Since these are wide angle lenses it stands to reason that you will use them much more at the wide end than at the 14 and 18mm end. Second most have 14 to 18 covered with the 14-42 zoom, with lesser IQ of course.

I really don't see lighting the 7mm end of the lens as being the issue you think it is. If it were no one would be using lenses like the 8mm fisheye and the Tokina 10-17. It is more an issue of technique and of course two strobes can be better than one although one can work quite well with many subjects.

The difference between 7 and 9mm may not seem like much but it is the difference between a 100 and 114 degree AOV. That is why, getting back to the Frink link above so many pro photographers and those with the resources are looking to house such wide rectilinear lenses for U/W work. Getting very wide is more about being able to get very close to the subject than anything else.

Phil Rudin
 
Phil, understand the quaility issue between the two lens (I only own the 7 -14 for that reason).

However, there is a major issue using any really wide angle rectilnear lens really close up...and it has nothing to do with putting it in an underwater housing.

I had to run outside and retest, just to make sure I am not blowing smoke... but this lens will focus to around 4 inches from the front of the lens (did not actually measure, but it is around that number.

From 4 inches, the field of view is approximately 11 inches (assuming I can read a tape measure correctly). At that point the corners of the image are actually almost 8 inches away. Just do a test image and you will see that the corners are essentially out of focus. You can make this better, obviously, by using a higher f-stop, and one obviously gets more depth of field from the smaller mm of the lens, but no lens can cover that huge of a difference.

Note: Just do a test image with a curved tape measure to see the effect, you can actually get sharp corners then.

Fish eye lens cover it because they are effectively a variable mm lens, with it being much smaller at the edges, and because the center is essentually a higher mm, you don't need to be as close to get the same center image size. Also, at the very edges, the images are so small as to make resolution fairly unimportant.


I use the lens a lot for commercial work, particularly where one needs a flat, wide field of view, and it's image quality around the 9 to 12 mm range is very good.

---------- Post added ----------

Phil, I absolutely love the level of technical detail you go into. But a couple of things:

1. The results can be no better than one would get on land, taking images without a case. I don't believe it is very practical to fix an existing lens issue.

2. By accident, you happen to have (in some images) the left hand person closer to the camera and the right hand person almost center in some and out to the right in others. Focus point may not have been exactly the same point in all of those images (but you would know far better than me on that issue).

There must be hundreds of different test one could make, and different conclusions you could make from doing one test like this. I would suggest that using a bit more scientific approach to might be quicker and answer a whole bunch of questions at the same time (not sure how much you know about experimental design, but this cries out for it)

I seriously wish there was more work done like this, so thanks for taking the time.






[
QUOTE=PHIL RUDIN;6379787]View attachment 127082View attachment 127083


To begin to understand how lenses as wide as the Panasonic 7-14mm work under a dome port you may want to read the attached, Digital Immersions: Pool tests for optimized corner performance on various wide angle lenses underwater

Here a test is being done with the Nikon 14-24mm zoom on a full frame camera with a nine inch GLASS dome port and a number of different extension ports. The 14-24 lens has the same 114 degree angle of view as the Pana 7-14 at the 7mm end of the lens. Among the findings is that an extension port with as little as a 5mm difference in length made a great difference in corner sharpness at 114 degrees. Expecting a one size fits all type of port to work with such a wide lens a bit of a pipe dream. Other lenses are tested as well and the less AOV the better the results. The Tokina 10-17 fisheye is also tested and like all fisheyes the results are better with less equipment.

Look at the ZEN ports, the 9-18/14-42 port has the same port glass as the 7-14 ZEN port but the ports are a different length to get best results. Second the glass has the same curve as a 170mm dome even though the glass is only around 100mm. The six inch Nauticam dome for the 7-14 zoom has a port equal to the curve of about a 230mm dome.

To compare the 7-14 to the 8mm fisheye is like apples to oranges. For best results with a fisheye you need a hemisphere not a curved port and it can be much smaller. The ZEN port for the Pana 8mm is the same glass as used for lenses like the Tokina 10-17 and Nikon 10.5 fisheye on APS-C sensors as well as the Canon 8-15 fisheye. The size of the dome alone allows you to get better CFWA than with the larger six to nine inch dome ports.

The bottom line is that the Panasonic 7-14 zoom can produce stunning results even with soft corners. The corner issue with any rectilinear lens as wide as 114 degrees is going to be the same and regarding your port selection you will likely get the results that you pay for.

The differences between rectilinear and fisheye are huge and I think most U/W photographers tend to tilt towards one or the other as their go to W/A lens.

The attached images give a little bit of an idea of how different the Panasonic 8mm fisheye is v. the Panasonic 7-14mm zoom at 7mm. Images taken 18 inches from the flat subject.

Phil Rudin[/QUOTE]
 
Hi Puffer Fish,

I have had a little trouble understanding how some of your remarks releate to my comments. So I will watch the Miami Heat game and get back to this in the AM after a little more thought.

Phil Rudin
 

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