GRD4 with GT-1

[Blow-in]

Pavel initiated a very interesting thread trying the GT-1 (teleconversion lens designed for the GRD2 - 1.43x to give an equivalent of 40mm) on the GRD3 (see viewtopic.php?f=53&t=3061).

There were rather mixed results and some of it may be to do with the thickness of the 43 - 37 mm step down adapter/ring required to make the GT-1 fit the GRD3 - the thicker the adapter the further away the converter lens is from the camera's lens increasing the vignetting and lack of corner sharpness.

Anyway, I decided to give it a go with the GRD4 as I have all the bits apart from the the step down ring which is coming in the post.

The 3 questions I want to answer are:

1 - Will cropping out the vignetting leave a useful amount of image? A 1:1 in-camera crop may do the trick. Alternatively using 1.2x digital zoom in 4:3 with autoresize may also work.
2 - Will the corners be sharp enough to give a usable image (after a crop)? This may depend upon the subject - scenery may not look as good as a portrait subject where soft corners can be an advantage.
3 - Will the results beat using the standard lens with 1.4x digital zoom with autoresize?

Once I have the adapter and a bit of time I hope to answer these questions but if anyone else has experience of using the GT1 on the GRD3 or 4 it would be good to know how they got on and what settings (if any) worked well. The adapter I've ordered is by Doerr - no idea yet whether it will be any good but it looked different to all the others I could find...which all looked to be from the same factory.

Richard

 

[streetshooter]

Richard,
A very interesting project your undertaking. Of course all of us will reap the rewards of your findings.

Question. Could you be satisfied, esthetically, with the image being blurred etc on the edges and corners? For me, I'd not see it as a detriment but as a new way to see with the camera.
Good luck with this and I make myself available if you need assistance in any way.

 

[Blow-in]

Thanks Don...I hope to have some answers in the next day or 2 provided the adapter arrives....life is a bit busy this weekend as the mother-in-law arrives on Friday evening (assuming broom stick services have resumed on the East Coast following weather disruption) and on Saturday we are taking the boats out of the water (part 1) which means a date with a 42 ton mobile crane....commonly known as displacement activity (last time the M-i-L visited I had to take the boat off the mooring for a few days to avoid really bad weather....needless to say it didn't materialise and my boating excuses are wearing a bit thin...).

Richard

 

[Wiener]

Hi guys,
this MIGHT help...
I have a TC-1 which must be a close relative of the GT-1? On the GX100 it will only produce vignetting-free results at max zoom, i.e. 72mm full-frame equivalent.
Therefore I am guessing that on the GRD4 it will produce quite severe vignetting at 28mm...but then, with the right subject, could still produce useable results?
Andy

 

[Blow-in]

TC-1 and GT-1 are related but not closely...TC is designed to work as a 'near doubler' at 72mm whereas GT is designed to work at 28mm with modest extension....GT thinks TC lacks focus in his life whereas TC thinks GT lacks in ambition - that's cousins for you.

 

[Rog Tallbloke]

My GT-1 works very nicely on my GXR A12-28mm Lensor. No soft corners.
download/file.php?id=15902

 

[Blow-in]

Rog,

That's encouraging - I assume you are using a step-down ring directly on to the lens - does it have a maker's name?

Richard

Post Script - I've just read the test again of the GXR with the converters (viewtopic.php?f=60&t=5578) which also found the GT-1 to be usable on the A28...requires a 40.5 - 37 step down. Jury still out on the GT-1 with the GRD4 - hopefully will come to a verdict soon!

 

[thelps]

assuming broom stick services have resumed on the East Coast

:lol: :lol:

I'll be keen to see your findings. I've never bought the GT-1 but I do have the GW-1, only used it occasionally but intend to keep it.

 

[Rog Tallbloke]

Rog,

That's encouraging - I assume you are using a step-down ring directly on to the lens - does it have a maker's name?

Richard, £2.49 with free delivery:
http://www.ebay.co.uk/itm/390347434759

No makers name, and it's a cheap far eastern solution, but the threads are fine, and it works a treat, so I'm happy. I put a skylight filter on the front of the ring when I'm not using the GT-1. Good protection for the Ricoh lens.

 

[Blow-in]

Rog,

Thank you...my adapter wasn't in today's post but maybe tomorrow. The A12 - 28 seems pretty versatile as it takes both the GW-2 or DW-6 and, with step-down, the GT-1 (I wonder if the GW-1 would also work in the step-down?). So from 21/22 mm to 28 to 40 - all at F2.5.

Richard

 

[rondo]

Count me in...will be looking forward to your results. and thanks for trying this!
just one thing:
-So from 21/22 mm to 28 to 40 - all at F2.5.
whenever the tele-converter subjects come up, i hear about the ability to use them without losing F stops.
yes, your camera will "think" that it has an as fast lens attached to it, but practically you will lose light: just check out the shutter speed that the camera selects with and without converter.

 

[Blow-in]

I arrived home late afternoon to find that the Doerr step-down adapter had also arrived....I'll do some proper comparisons when I have time but I couldn't resist having a quick go to see how it worked. For simplicity I went straight to 1:1 (7M Jpg).

I was also quickly reminded by the low sunlight just how much flare the GT-1 can produce.

Thoughts so far is that this is a usable lens for portraiture and also for macro but corner softness is a real issue for scenery...however I want to see what happens with a combination of the GT-1 and some mild digital zoom.

Anyway, spot the Mother-in-Law (I got her to remove her pointy hat for the shot) - just some initial quick shots...

Richard

PS ignore the focal length in the exif - my GRD4 thinks I have the DW-6 attached

 

[rondo]

nothing new here, i'm afraid? i assume you would agree...
these samples are as unusable as the ones shared on the other thread. (or as usable: if you think it's acceptable-but even with square cropping the corners are terribly blurry....)
how thick is the adapter? you really need something very thin. actually the previous thread has a better performing sample.
thanks for sharing your findings with us.

 

[Blow-in]

nothing new here, i'm afraid? i assume you would agree...
these samples are as unusable as the ones shared on the other thread. (or as usable: if you think it's acceptable-but even with square cropping the corners are terribly blurry....)
how thick is the adapter? you really need something very thin. actually the previous thread has a better performing sample.
thanks for sharing your findings with us.

I need to play a bit more before I admit defeat...I'll do an accurate measure of the effective depth of the ring with digital callipers when I have some more time..the critical measurement needs to be taken from the back of the lens I think to the edge of the GH-2. I also want to play with some different apertures (these were fully open) to see if that makes a difference at the edges. I also think that digital zoom together with the GT-1 may produce something interesting....when you shoot 1:1 you end-up with a 7M image...using digital zoom @ 1.2x on 4:3 with auto resize the image is 8M....sitting here I've just shot one image posted below with the latter settings on a high ISO.....not sure but there may be some thing to work with with a focal length of 48mm equivalent.

Richard

 

[Blow-in]

I had a few minutes this morning so took the GRD4 with GT-1 shots below using 4:3 and some digital zoom (with auto resize).

You can see for yourself that the vignetting is relatively mild (easy to crop out) but the corner softness is quite apparent.

Whether you can get a usable picture with this combination is probably subject dependent.....might be OK for a picture where only the centred subject needs to be sharp....a portrait for example.

I want to try in camera vignetting to see the effect. I've yet to measure the Doerr ring thickness but it is pretty thing when mounted.

I also wonder if I have a slight centering issue. The left side seems softer than the right despite being square on and correcting tilt in both planes.

The quest continues!

Richard

 

[Wiener]

TC-1 and GT-1 are related but not closely...TC is designed to work as a 'near doubler' at 72mm whereas GT is designed to work at 28mm with modest extension....GT thinks TC lacks focus in his life whereas TC thinks GT lacks in ambition - that's cousins for you.

Hi Richard,
just after posting and switching off my machine, my brain flashed with inspiration (or as close to this as can be managed) and concluded as you describe.
Thanks for saving me having to post the correction!
Andy

 

[radical7]

Here's an option: Make a petition and ask Ricoh for a 50mm!!!