Fitting DX lenses on an FX body

[lerabu]

What I am going to ask here is boredering on the line with heresy but I have to ask anyway... :P

I am stashing away money to upgrade from my D80, which I am very happy with, but as I have many, many low light situations which require fast shutter speed I am looking to upgrade to something that can handle noise better.

I have recently bought an SB-700 which has allowed me to go down to ISO 800 but the noise removal sometimes means a loss of sharpness to the photos.

The main debate is between either a D7000 or a D800 (when it comes out). The decision is going to come when the full specs come out for the latter, but what is being announced so far sounds great!

Of course the question of FX glass is upon this choice and going to an FX camera one would shoot you if you were to stick a DX lens on it. Usually when you stick a DX lens on an FX camera, the camera adapts and uses only the cropped part of the sensor, however this can be overridden and the camera stays full frame. This leads to heavy vignetting at wide angle focal lengths but gets better when you increase focal length.

Question 1: Has anyone tested the kit lens 18-105mm 3.5-5.6G VR on a D700? From which point (in terms of mm) is the vignetting negligible.

Question 2: When moving from DX to FX would you suggest going for several zoom lenses or stick with primes? One for wide angle, a 50mm and maybe a protrait lens upward of 80mm? I As I currently have a 50mm lens FX, I was thinking of getting a 20mm prime and I don't know about a prime tele yet, I lean towards the wide angle part

I very much appreciate your taking the time to read! If you have any useful information on the topic it is most welcome!

[ravncat]

Originally Posted by lerabu

This leads to heavy vignetting at wide angle focal lengths but gets better when you increase focal length.

Question 1: Has anyone tested the kit lens 18-105mm 3.5-5.6G VR on a D700? From which point (in terms of mm) is the vignetting negligible.

Question 2: When moving from DX to FX would you suggest going for several zoom lenses or stick with primes? One for wide angle, a 50mm and maybe a protrait lens upward of 80mm? I As I currently have a 50mm lens FX, I was thinking of getting a 20mm prime and I don't know about a prime tele yet, I lean towards the wide angle part

Where a crop lens vingettes depends more on the lens design, but in general you are right.

1. I've not tested that lens, so I can't help you there. My 18-70 never really got clear of vignetting, and my 18-200 (if i recall, i should double check) had vignetting at the wide and telephoto end, but was rather ok somewhere towards the telephoto end.

2. This is a question for your style of shooting an your preferences not so much just DX/FX - I use a lot of primes personally, but alot of people don't want to carry as many primes as you would want for better framing control. (That's where zoom's stand out, a prime tends to force a perspective for a given framing (Unless you have lots of primes to switch between)- zooms let you choose a perspective and then choose framing)

Depending on what you have, it may be cheaper to go the prime route in the short term, but you'll give up the convenience that is zoom. Don't discount the d7000 or the eventual d400 - they're both a big step up in low light performance from your d80 (As someone who went from a d200, which is the same sensor as the d80 to a d700 (I had several prime lenses and a zoom so I was not so affected by the jump)

[OsmosisStudios]

You should be able to go down to ISO 100 or 200 with an SB-700 mounted. I regularly shoot 1/125, f/5.6, iso 200 on a D300s with an SB unit (600 or 800) and never have an issue. I dont know where you're getting this ISO 800 business.

[lerabu]

Originally Posted by ravncat

Where a crop lens vingettes depends more on the lens design, but in general you are right.

1. I've not tested that lens, so I can't help you there. My 18-70 never really got clear of vignetting, and my 18-200 (if i recall, i should double check) had vignetting at the wide and telephoto end, but was rather ok somewhere towards the telephoto end.

2. This is a question for your style of shooting an your preferences not so much just DX/FX - I use a lot of primes personally, but alot of people don't want to carry as many primes as you would want for better framing control. (That's where zoom's stand out, a prime tends to force a perspective for a given framing (Unless you have lots of primes to switch between)- zooms let you choose a perspective and then choose framing)

Depending on what you have, it may be cheaper to go the prime route in the short term, but you'll give up the convenience that is zoom. Don't discount the d7000 or the eventual d400 - they're both a big step up in low light performance from your d80 (As someone who went from a d200, which is the same sensor as the d80 to a d700 (I had several prime lenses and a zoom so I was not so affected by the jump)

Thank you for you answer! When I was buying the D80 I was on the fence between it and the D200!

I guess there is no way of knowing until I try it somehow, regarding the lens vignetting. I will look into the D400 also for low light performance, it's a good point!

Given the prices of FX zooms and the depth of my pocket I would either gor the prime route, I love shooting with primes! Or stay on the DX platform

Originally Posted by OsmosisStudios

You should be able to go down to ISO 100 or 200 with an SB-700 mounted. I regularly shoot 1/125, f/5.6, iso 200 on a D300s with an SB unit (600 or 800) and never have an issue. I dont know where you're getting this ISO 800 business.

Hi! Thank you for your answer! I have tried shooting at ISO 100, 200 and it really works well! With the flash at full power ISO 100 isn't an issue. I was shooting ISO 800 as I wanted to get some ambient light into the shots also, which wasn't possible at ISO 100 I suppose it really depends on what you want to show in you picture, but you will know better than me as you have a lot more experience!

I am also in situation where I would like to shoot without the flash so a good performance in low light is really important to me.

[OsmosisStudios]

Originally Posted by lerabu

Hi! Thank you for your answer! I have tried shooting at ISO 100, 200 and it really works well! With the flash at full power ISO 100 isn't an issue. I was shooting ISO 800 as I wanted to get some ambient light into the shots also, which wasn't possible at ISO 100 I suppose it really depends on what you want to show in you picture, but you will know better than me as you have a lot more experience!

I am also in situation where I would like to shoot without the flash so a good performance in low light is really important to me.

You can always slow the shutter speed down; I often shoot at 1/60 and get plenty of ambient in most of my shots. Or move up to ISO 200. There's really no need to go to 800.

[lerabu]

Originally Posted by OsmosisStudios

You can always slow the shutter speed down; I often shoot at 1/60 and get plenty of ambient in most of my shots. Or move up to ISO 200. There's really no need to go to 800.

I will try that! Thanks!

Do you put the flash on TTL or set up the flash power manually? If the flash is pushed to 1/4 power and upwards how bad does it hurt the flash's life longevity?

[OsmosisStudios]

Pushing the flash wont hurt it's lifespan; theyre designed to run full-power. The only issue you might find is if you're doing full-power dumps in quick succession; it could overheat.

I set the flash to TTL-BL, point it straight up, and use the bounce card built into it. Set TTL +1 2/3 and enjoy.

[lerabu]

I will try that!

About the overheating, when the flash discharges at full power, the air around it does smell a bit burnt!

[OsmosisStudios]

Originally Posted by lerabu

About the overheating, when the flash discharges at full power, the air around it does smell a bit burnt!

Just ozone. That's normal. What happens is when you dump that much power out of the capacitor, it gets warm and doing it several times in a row can cause the unit to warm up. The SB-700 will slow itself down when it gets too hot. Unless you're doing 6-7 in a row very quickly, you wont have to worry